Competing Visions of Restraint

Politics can make strange bedfellows, even in debates about U.S. grand strategy. In late 2002 and early 2003, the approaching invasion of Iraq elicited opposition from realists, progressives, and conservatives. Academic realists argued that Saddam Hussein could be contained and thus war was unnecessary.¹ In Washington, dissenting voices on the left and right agreed that Iraq did not pose an urgent enough threat to justify the potentially high costs of an invasion and prolonged occupation.² Those who opposed the Iraq War also began to question other elements of the war on terrorism, such as the expanded nation-building mission in Afghanistan. They came to advocate for ending what they later termed “endless wars.”³ Over time, that position coalesced into a larger critique of prevailing U.S. grand strategy—one that highlighted damaged relations with other major powers, unhealthy alliance dynamics, failed military interventions, and dysfunction at home—and an alternative set of proposals that came to be known as restraint.⁴ More than twenty years on, what are the ideas that underpin the restraint position? What impact will these ideas have on the direction of U.S. grand strategy going forward?⁵

We find that restraint is a big tent, which is a double-edged sword for its influence on U.S. grand strategy. On the one hand, there are multiple pathways to a grand strategy of restraint, rooted in realist, conservative, and progressive principles. So, under certain domestic and international conditions, a broad coalition in favor of restraint could emerge. On the other hand, the fact that restraint is a big tent means there are competing visions within it, making it difficult for restrainers to coalesce around common arguments and a shared set of policies.⁶ Most notably, we argue that deep and growing differences on China will complicate the restraint camp's ability to provide a clear alternative to prevailing U.S. strategy in East Asia. Still, most restrainers will likely remain united around calls for U.S. retrenchment from Europe and the Middle East. Even if restraint remains a minority position, a better understanding of its logics is valuable for considering its impact on future U.S. policy choices.

The next section situates restraint within the broader debate about U.S. grand strategy. We then discuss our approach to developing a typology of restraint. We present the competing visions of restraint, discussing realist, conservative, and progressive versions in turn. We then chart how changes in the strategic landscape—including Russian aggression and China's growing power—are reshaping areas of agreement and disagreement among restrainers. Finally, we conclude by discussing how restraint might influence the future direction of U.S. grand strategy.

Restrainers’ numbers in academia and influence in Washington were limited for many years. Writing in the mid-1990s, Barry Posen and Andrew Ross captured the grand strategy debate that followed the end of the Cold War, identifying four distinct schools of thought: neo-isolationism, selective engagement, cooperative security, and primacy. Their article describes neo-isolationism as “the least ambitious, and, at least among foreign policy professionals, probably the least popular grand strategy option.”⁷ Tellingly, Posen and Ross described prevailing U.S. grand strategy in the Bill Clinton administration as “selective (but cooperative) primacy,” a hybrid strategy that rejected neo-isolationism while drawing on elements of the other three grand strategic positions.⁸ In the years that followed, the war on terrorism reflected the triumph of a more muscular version of primacy in Washington.

Restrainers’ voices in the grand strategy debate have strengthened since then, increasing the value of understanding their ideas and how they might contribute to future U.S. policy choices. From the four options that Posen and Ross identified in the mid-1990s, the grand strategy debate coalesced into two poles amid the Iraq War: deep engagement and restraint.⁹ Deep engagement calls for the United States to remain a security leader in three key regions (East Asia, Europe, and the Middle East) through commitments to allies and partners, a role made credible by its forward military presence. Beyond this core set of prescriptions, there are deep divisions among “deep engagers,”¹⁰ including about how ambitious U.S. aims should be and what role liberalism and multilateralism should play in U.S. foreign policy.¹¹ The restraint camp includes the neo-isolationists that Posen and Ross discuss as well as a much larger group calling for less dramatic reductions in U.S. military involvement across the globe.

Concerns about U.S. overreach in the war on terrorism reenergized the grand strategy debate within academia and made more scholars sympathetic to restraint.¹² More recently, interest in restraint has grown in the public sphere. Restrainers’ calls to end the endless wars in the Middle East gained support on both sides of the aisle.¹³ Elected in 2016, President Donald Trump did not adopt a grand strategy of restraint,¹⁴ but he did voice restrainers’ concerns about alliances and adopt some policies that restrainers applauded, such as negotiating a U.S. withdrawal from Afghanistan.¹⁵ Since then, Republicans have adopted a platform that includes calls for a stronger military as well as restraint-friendly themes, such as using force “sparingly” and promoting allies’ burden sharing.¹⁶ Although restraint remains a minority view, the shift in the distribution of power away from the United States and the costs and risks associated with intensified great power competition could draw more supporters to the restraint position and produce a shift in U.S. grand strategy in the future.¹⁷

Given its growing relevance, we offer a typology of restraint focused on restrainers’ underlying ideas, doing for restraint what Posen and Ross did for the grand strategy debate more generally. Restraint, as we describe it in this article, is a big tent comprised of groups with different intellectual backgrounds that nonetheless share a commitment to several grand strategic prescriptions.¹⁸ Our typology aims to bring order to the complex landscape of restraint so that analysts, policymakers, and the public can better engage with and critique its ideas and evaluate its trade-offs. Understanding the ideas that motivate restrainers is also the first step toward predicting how their policy positions and influence may change as international conditions evolve.

We identify restrainers on the basis of their grand strategic prescriptions and then examine the ideas that motivate these positions.¹⁹ We consider analysts to be restrainers if they call for substantially reducing U.S. military engagement in at least one of the key regions of East Asia, Europe, or the Middle East. Reducing military engagement includes attempting to address or resolve conflicts of interest with U.S. rivals; rebalancing, downgrading, or ending U.S. alliances and security partnerships; downsizing the U.S. forward military presence; and setting a high threshold for the use of force. In other words, restrainers oppose deep engagement in at least one region that deep engagers consider crucial to U.S. security. Restrainers, in our definition, argue that the United States should be, at most, the security provider of last resort in one or more of these regions. Given this broad definition, we include those who promote restraint in one region even if they prescribe deep engagement in another.

Next, we examined restrainers’ writings and conducted interviews to determine their motivating beliefs and group them into categories. We interviewed sixteen restrainers from June 2022 to June 2023 (thirteen from think tanks and three from academe). We limited our search to think tank analysts and academics because they more explicitly and consistently connect their underlying beliefs to their foreign policy preferences. We excluded politicians and activists from our analysis.

For each group, we describe its definition of U.S. interests and threats to those interests, as well as its beliefs about international politics and the policies that are best suited for responding to those threats. We identify the ideas that unite each group as well as the disagreements among its members. As with any typology, individual analysts may not perfectly align with the ideal type categories that we construct.

The ideas that have brought people to restraint since the early 2000s may lead them to different policy prescriptions as conditions change. We therefore consider restrainers’ views on contemporary security issues, such as Russia's full-scale invasion of Ukraine, China's rise, and the defense of Taiwan. If analysts have not written on these issues, we proceed deductively, applying the motivating ideas described in the typology to predict the preferences of the group on a specific policy issue.

Our core finding is that there are competing visions of restraint: multiple pathways have converged on restraint's broadest prescriptions in recent decades, even as important policy differences remain.²⁰ In brief, realist restrainers argue that deep engagement has been counterproductive as states balance against perceived threats from U.S. military presence, security relationships, and uses of force. Conservative restrainers oppose deep engagement because they think that it undermines their definition of the American way of life. Progressive restrainers believe that deep engagement perpetuates injustice and uses military tools for problems that require alternative solutions (see table 1).

Each group also has other concerns that can, under some conditions, push them toward deep engagement: realist restrainers worry about maintaining the balance of power; conservative restrainers are concerned about other powers’ ability to influence the American way of life; and progressive restrainers support solidarity with other democracies. Subgroups of realists, conservatives, and progressives assign different weights to these competing considerations, leading to important policy differences that we detail in this article. Only the realist restrainers explicitly root their arguments in a theory of international politics. The other two groups start from theories of politics in general, which in turn influence how they view international relations. What unites all these groups, despite their differences, is a current preference for restraint over deep engagement.

The changing strategic and domestic landscapes may have countervailing effects on restraint's potential influence on policy going forward. On the one hand, international and domestic developments could increase interest in restraint. For example, if great power competition threatens to escalate to major war between nuclear-armed powers—exactly the outcome restrainers seek to prevent—restrainers’ calls for a less militarized approach toward rivals and greater reliance on diplomacy could become more persuasive to policymakers and the public. Moreover, the decline in U.S. relative power, fiscal pressures, and domestic challenges could make it difficult to sustain the military advantages and commitments deep engagement demands. The big tent of restraint offers multiple entry points—stemming from realist, conservative, and progressive principles—for those who seek alternatives to deep engagement.

Yet there are also pressures to move away from restraint, including Russian aggression and China's rise. For example, realist restrainers such as John Mearsheimer have already concluded that the time to balance aggressively against an increasingly powerful China is now.²¹ Conservative restrainers may become less committed to restraint in East Asia as China's power grows. As they view it, a more powerful China could increase its ability to influence the American way of life. Progressive restrainers seek to balance their desire to cooperate with China on vital issues like climate change and their opposition to authoritarianism and the threat it poses to democracies in the region. The difficulties that restrainers have in developing a common China policy are emblematic of a broader problem: Any position animated by competing visions will struggle to provide a clear alternative to prevailing U.S. grand strategy.

Restrainers’ ability to unite behind a single set of policy preferences, or their inability to do so, is only one determinant of their overall influence. U.S. fiscal constraints, domestic politics, and changes in the strategic landscape influence the size and effectiveness of any coalition for grand strategic change. Still, our analysis of restraint's internal debates suggests that restrainers largely agree that the United States should retrench from Europe and the Middle East. This unity could mean restrainers gain greater political impact on future policy in these regions than in East Asia, about which they are more divided.²²

Grounded in balance of threat theory, realist restrainers developed some of the most in-depth critiques of post–Cold War grand strategy, parts of which other restrainers now draw on.²³ Their primary argument is that deep engagement is self-defeating because other states, threatened by U.S. forward military presence, alliances, and the frequent use of force, balance against the United States. A distribution of power that is shifting away from the United States makes pursuing a strategy of deep engagement in multiple regions even more unsustainable.²⁴ Like all three groups we examine, realist restrainers have internal disagreements. They differ on how dangerous the rise of another hegemon would be for U.S. interests. Likewise, they disagree about the trade-offs associated with maintaining a strategy of deep engagement in Asia.

Not all realists are restrainers. Some advocates of deep engagement draw on another realist logic, hegemonic stability theory, which holds that strong states promote stability by enforcing rules, providing public goods like security, and promoting collective action on shared challenges like responding to aggression.²⁵ Hereafter, we use the term “realist” to refer only to realist restrainers.

Realists hold a narrow view of vital U.S. interests, which they define as the security and sovereignty of the United States: maintaining territorial integrity, preventing attacks on the U.S. homeland and territories, and limiting foreign interference in U.S. domestic politics.²⁶ Some realists add maintaining the United States’ prosperity²⁷ or position as the world's top military power to the list of vital interests.²⁸

Realists believe that geography, nuclear deterrence, as well as the size, diversity, and dynamism of the U.S. economy insulate the United States from most threats. In their view, the countries that border the United States are relatively weak militarily, and two vast oceans make it difficult for a state in another region to project significant power into North America. If another power tries to disrupt U.S. trade in other regions, the United States can easily adapt because it has a large and diverse economy and major economic partners in its own region.²⁹

Given the United States’ strategic setting, realists believe that U.S. vital interests would be threatened by the rise of a regional hegemon in only one of three core regions: East Asia, Europe, or the Middle East. A regional hegemon can dominate its region militarily and economically, as the United States does in the Western Hemisphere. Such a state is especially dangerous if, having subdued its own region, it can aggregate the resources to project power globally without having to worry about local threats.³⁰ Realists disagree about just how large a threat a regional hegemon would pose and therefore how aggressively the United States should balance against any that begin to emerge.

Realists assume that states base their threat assessments primarily on other states’ relative power, geography, and behavior.³¹ These restrainers argue that the combination of U.S. power and foreign policy choices, such as the frequent use of force, alliance enlargement, and sizable forward military presence, make U.S. rivals insecure and sometimes aggressive. As Stephen Walt puts it, “Relentless efforts to enhance one's power at the expense of others are usually self-defeating, because other states will eventually join forces to check a powerful state and contain its ambitions. A corollary to this principle is that threatening a great power's vital interests—especially near its home territory—is bound to provoke a harsh reaction.”³² Insecurity leads U.S. rivals to spend more on defense and cooperate with one another to balance against the United States. These dynamics can increase the risk of war.³³ For example, realists argue that North Atlantic Treaty Organization (NATO) enlargement contributed to Russia's insecurity and decision to seize Crimea in 2014 and launch a full-scale invasion of Ukraine in 2022, in part to forestall Ukraine's entry into NATO. Realists also believe that U.S. military engagement and use of force globally has contributed to the deepening relationship between China and Russia.³⁴

Beliefs about balancing also shape realists’ views of alliance dynamics. Realists believe that states have incentives to preserve their power. In the face of threats, therefore, they prefer to engage in buck-passing, or letting other states expend their resources balancing against a shared threat. In this view, allies will take a free ride from powerful patrons like the United States when they can. Yet nationalism leads states to fiercely resist coercion and conquest, so states balance when necessary to counter powerful aggressors.³⁵ Realists believe that the motivation to balance is so strong even rivals will usually vercome their differences to work together to prevent the emergence of a regional hegemon. These strategists acknowledge that the United States may need to intervene when local powers are collectively too weak to counter a powerful aggressor, as in Europe during World War I, World War II, and the Cold War.³⁶

In addition to viewing many alliances and partnerships as unnecessary, realists think that these relationships can be dangerous. In this view, alliances and partnerships create the risk of entanglement, whereby a security relationship draws a state into a conflict that is not a threat to its own interests. For example, a state might fight to protect its reputation for defending allies, or it might fight because the state begins to treat an ally's interests as its own.³⁷

Realists are attentive to the ways nuclear weapons shape international politics. They believe that a state with a secure second-strike capability can reliably deter large-scale conventional attacks on its homeland. At the same time, realists are profoundly concerned about the risks of nuclear escalation in conflicts between nuclear-armed states. They believe that such risks are only worthwhile to protect vital interests. These thinkers argue that extended nuclear deterrence is dangerous. To signal a strong willingness to use nuclear weapons to defend an ally, states adopt policies (e.g., forward basing of nuclear weapons in allied countries) that increase security competition and the risk of nuclear use. Realists believe that threats of nuclear use to defend the homeland are inherently credible, so some support wealthy U.S. security partners developing their own safe and secure nuclear forces.³⁸

Realists believe that a state's economy is the long-term basis of its military power. They also argue that diverting too many resources to defense instead of to programs that support long-term domestic economic growth (e.g., infrastructure, education) can harm a state's economy. Therefore, realists pay attention to limited resources, reinforcing their argument that the United States should use military power only to advance a narrow set of vital interests.³⁹

Realists do not see a near-term prospect of a regional hegemon emerging in Europe or the Middle East. Realists have called for the United States to use diplomacy to settle conflicts of interest with Iran and Russia.⁴⁰ They believe that local powers can effectively balance against both countries and would have more incentive to do so if the United States were to draw back militarily from these regions.⁴¹

Realists agree that China is the only potential regional hegemon the United States faces.⁴² They prefer to let local powers take the lead in balancing against potential regional hegemons for as long as possible but are acutely aware of impediments to balancing and the difficulty of precisely assessing the distribution of power.⁴³ Therefore, most of these realists prefer containing China in East Asia before it can project significant power into the Western Hemisphere or represent an imminent threat to the U.S. homeland.⁴⁴

Realists disagree on the conditions under which the United States should take steps to reduce China's influence in East Asia.⁴⁵ At one extreme, some believe that the United States could tolerate China's domination of its region as long as the United States sustained a secure second-strike capability and sufficient conventional capabilities to defend the homeland.⁴⁶ On the other extreme are realists who favor sustaining the current policy of containing China now, including by preparing to intervene militarily to defend Taiwan and strengthening existing alliances.⁴⁷ Most realists are between these extremes, believing that the United States should retrench to some extent but maintain the military capability to prevent China from coercing Japan or dominating waterways beyond its immediate periphery. Given the costs of great power war, the risk of nuclear escalation, and limited U.S. interests, this subset of realists is unwilling to use force to defend Taiwan or sustain U.S. access to areas on China's periphery, such as the South China Sea. These restrainers seek to shift more responsibility to U.S. allies but generally do not call for eliminating U.S. alliances or forward presence in East Asia.⁴⁸

Unlike their realist counterparts, conservative restrainers’ main concerns are domestic rather than international. For some conservatives, external threats loom large and justify a strategy of deep engagement.⁴⁹ Conservative restrainers, in contrast, view traditional U.S. grand strategy itself as the larger threat. In their view, deep engagement undermines the American way of life.

Two strands of thought that animate and sometimes divide the conservative movement—classical liberalism and nationalism—underlie calls for restraint. Conservative restrainers are often motivated by a mix of these ideas. For simplicity, we talk about two ideal type groups. Classical liberals’ overriding concerns are that deep engagement reinforces the “garrison state,” a powerful, unaccountable executive branch that threatens individual liberty and republicanism and disregards the limits of U.S. power.⁵⁰ Nationalists, drawing on principles of traditionalism and communitarianism, are more concerned with how deep engagement influences American society and traditions.

Classical liberals want to preserve the key tenets of the American way of life, which they define as liberty and republicanism at home. In other words, they are “negative liberals” who possess an anti-statist orientation, are hostile to centralized power, and advocate a minimal role for government.⁵¹ Negative liberals, as Brendan Rittenhouse Green argues, “perceive a fundamental tradeoff between commitments abroad and liberty at home.”⁵² Most problematic is war itself.⁵³ In the words of John Glaser, “War and government power are intimately connected…. During times of war, the state centralizes power, raises taxes, proliferates bureaucracies, violates civil liberties, and usurps more control over the economy.”⁵⁴ Like realists, classical liberals believe that the more the United States makes commitments abroad, the more wars it will be entangled in.⁵⁵ Although classical liberals view war as the biggest threat to liberty, they believe that deep engagement requires states to manage and respond to threats stemming from far-flung commitments. This can lead the government to take steps that endanger liberty, even in peacetime. Consequently, they view deep engagement as problematic even when it does not lead to war.⁵⁶ In this respect, classical liberals explicitly link their arguments to those of the founders, who warned about the association between alliances, war, and an overly strong state.⁵⁷

Classical liberals believe that deep engagement also threatens key elements of republicanism: public participation, keeping decision-making as local as possible, and constitutional checks and balances.⁵⁸ In the classical liberal view, deep engagement has given rise to an unaccountable executive; the American people and their representatives are unable to monitor or influence a large and active bureaucracy that is managing events across the globe. The military, in particular, has an outsized role in U.S. politics. Moreover, alliances and involvement in less accountable international institutions move decision-making even further away from the local level. The founders’ attempt to constrain a warlike executive branch is a failed project according to the classical liberal perspective. Classical liberals view U.S. governance as heavily skewed toward executive power, evidenced by Congress ceding its authority to declare war.⁵⁹

Apart from their fears of a garrison state, classical liberals are skeptical of utopian ambitions.⁶⁰ Just as they are leery of social engineering at home, classical liberals are doubtful of the United States’ ability to shape events in other parts of the world. As Stephen Kinzer puts it, “Conservatives do not believe that any country can solve the world's problems or is called to do so.”⁶¹ Classical liberals are especially opposed to nation-building. Every country has its own history and culture, they argue, which makes it difficult for the United States to impose solutions beyond its own borders. Indeed, the law of unintended consequences reigns, and attempts at social engineering produce more harm than good. This is why, according to Jerry Hendrix, “conservatives do not seek to actively impose their ideas upon other nations.”⁶² Instead, classical liberals want the United States to become an exemplar of democracy, working to strengthen its own country rather than going abroad “in search of monsters to destroy,” as John Quincy Adams put it.⁶³

Consistent with their desire to reign in foreign commitments, classical liberals define the national interest narrowly. Specifically, they argue that the United States should prioritize protecting the physical security of the homeland and the American way of life.⁶⁴ Classical liberals tend to support free trade (with some national security exceptions). Among libertarians, a subset of classical liberals, the view that capitalism and peace go together reinforces their traditional commitment to free trade and wariness of mercantilism.⁶⁵

Although classical liberalism motivates this group's desire for a restrained grand strategy, realism provides the intellectual architecture for many of the arguments they invoke on foreign policy.⁶⁶ First, both groups start from the premise that favorable geography and power advantages insulate the United States from external threats. They expect other states to balance against potential hegemons, and they generally believe that conquest no longer pays. For these reasons, the United States does not need to do much to ensure its security.⁶⁷ Second, these groups agree that, in theory, another hegemon could pose a sizable enough threat to the United States to warrant a balancing response. Third, there are differences within each group about when the United States should step in and balance against a hegemonic threat, as we discuss in the next section. Fourth, both groups view the international system as competitive and believe that the United States needs a capable military to protect itself.⁶⁸ As W. James Antle puts it, “Conservatives are not pacifists.”⁶⁹ This belief stems from their view that human nature is “unchanging” and people are fated to be “warring, competitive and wanting.”⁷⁰ Even so, libertarians tend to be more optimistic than realists and other conservatives about states’ ability to overcome competition, such as through deepening economic interdependence.⁷¹

Although classical liberals favor maintaining a capable military, albeit a smaller one than deep engagement requires, they prefer the United States be more restrained in its use of military power. Generally, they privilege diplomacy, commerce, and cooperation over the use of force.⁷² Classical liberals are especially opposed to “protracted … war[s] of choice,” such as Afghanistan and Iraq.⁷³ They believe that the United States should intervene militarily only in the rare cases when vital security interests are at stake. Such missions should occur as a last resort and be backed by a national consensus and obtainable military objectives.⁷⁴

In the post–Cold War period, classical liberals have been among the most committed restrainers.⁷⁵ With the United States secure and the international environment relatively benign, they argue that privileging military power so heavily in U.S. grand strategy creates more problems than it solves.⁷⁶

Nationalists, as Colin Dueck explains, “focus on preserving and promoting (the United States’) interests, rights, values, security, traditions, and way of life, believing that it is entirely legitimate to do so.”⁷⁷ Deep engagement, they argue, has produced a cosmopolitan foreign policy elite that is oriented toward global problems rather than national interests.⁷⁸ Prominent again in the public sphere, nationalists invoke ideas that “paleoconservatives” such as Patrick Buchanan espoused in the 1990s.⁷⁹

Nationalists and classical liberals have much in common. Both groups privilege the national interest, believing that the United States has a limited ability to shape events abroad and deep engagement threatens the American way of life. But these two groups diverge in a few important areas relevant to grand strategy.

First, classical liberals mistrust nationalism because it is associated with militarism and a strong state.⁸⁰ Second, and more fundamentally, nationalists differ from classical liberals in describing the American way of life they are trying to protect. Nationalists are less animated by concerns about individual liberty and republicanism. Instead, they view deep engagement as a threat to traditional American culture and society. Indeed, some nationalists are arguably anti-liberal, prioritizing the “common good” of the group (e.g., family, community, and nation) over the individual.⁸¹ Traditionalist and communitarian impulses lead these conservatives to worry about how deep engagement's globalism affects U.S. society. For example, nationalists believe that unfettered economic globalization has fueled economic inequality and, therefore, political divisiveness at home. This group also worries that economic relationships create a pathway for foreign influence in the United States. In addition, nationalists view U.S. openness to immigration as a threat to American culture. They thus call for greater protectionism, whereas classical liberals generally support free trade.

Nationalists have yet to articulate their views on grand strategy in the detailed way that classical liberals have. That said, the increasing prominence of nationalist ideas among conservatives could complicate the relationship between conservatism and restraint going forward. Nationalists do seem to be restrainers in that they are leery of the commitments and entanglements that characterize deep engagement. But they are also hard-liners, to use Dueck's terminology. In his words, “the basic hardline instinct is to maintain very strong defenses, punish severely any direct threat to U.S. citizens, refuse international accommodations, and otherwise remain detached from multilateral commitments.”⁸² Which of these instincts will prove to be more influential among nationalists will probably depend on U.S. domestic politics and changes in the strategic landscape.

Like their realist counterparts, conservatives tend to be alliance skeptics. They regularly echo realist complaints that allies get a free ride from U.S. security guarantees and alliances risk entangling the United States in conflicts that are not in its national interest.⁸³ Some would like the United States to avoid permanent alliances entirely.⁸⁴ Others support a reduced U.S. role within existing alliances.⁸⁵ Conservatives can afford to be alliance skeptics because, in their view, there is no hegemonic threat on the horizon—certainly not one in Europe or the Middle East.

Mirroring divisions in the realist camp, conservatives have a range of views about what U.S. policy toward China should be. Many conservatives believe that formidable obstacles (e.g., local balancing, the difficulty of projecting power) hinder China's prospects for attaining regional hegemony.⁸⁶ Even if it could overcome these obstacles, China would pose more of an economic threat than a military one. Although it is unlikely China could seriously threaten the U.S. homeland, it could undermine U.S. prosperity. These conservatives might accept the United States joining a balancing coalition led by local powers, but because the threat is limited, they would want it to adopt an offshore posture to minimize the risk of direct involvement in any war.⁸⁷ Given that China is not a major threat to the United States, these conservatives fear that current U.S. policies, such as deepening alliances and partnerships and a building up of conventional weapons in the region, are unnecessary and fuel unnecessary competition.⁸⁸ Diplomatically, coexistence is the ultimate goal; they prefer the United States make a greater effort to acknowledge China's vital interests, most importantly when it comes to Taiwan.⁸⁹ Yet some conservatives are more uneasy about the prospect of China dominating its region, which they fear would allow it to project power into the Americas. These conservatives are thus willing to balance against China sooner than others in the group, but they too want U.S. policy to be less confrontational than it is now.⁹⁰ There are, however, conservatives who support current U.S. policy or something even more hard-line.⁹¹

The political left in the United States holds a range of views on foreign policy. Here we focus on progressives who call for the United States to have a less militarized approach to the world. This group is united by a belief that developments at home and abroad are highly interdependent, a view shared by advocates of deep engagement. Yet progressives depart from deep engagers on methods: Restrainers on the left believe that deep engagement makes the United States excessively militarized. U.S. policymakers, in this view, often use the military to solve problems that do not have a military solution.

Like conservatives and realists, progressives have internal differences on policy. Most notably, they disagree about how to weigh their desire to stand in solidarity with other democracies and their concerns about the damage done by using military tools to do so.

Progressives start with a more expansive set of interests than other restrainers. Progressivism maintains that the tools of the state should be wielded to improve social and economic opportunity for all.⁹² Therefore, as Van Jackson describes it, progressives seek the “pursuit of a more just world.”⁹³ In addition to securing the U.S. homeland and territories and U.S. domestic autonomy, progressives believe that democracy, human rights protections, greater economic equality, and environmental sustainability globally are all vital U.S. interests (though they disagree about how to prioritize these interests).⁹⁴ Progressives base their view of U.S. interests on principle—justice should not end at the U.S. border—and on the belief that developments abroad and conditions at home are interdependent.⁹⁵ In the words of Kate Kizer, U.S. security “is dependent on the security of others” because instability abroad threatens to reach the homeland.⁹⁶

Progressives also assess threats differently than other restrainers. Progressives acknowledge that geography and relative military power make the United States safe from conventional attacks by a foreign power.⁹⁷ Yet they believe that there are many transnational threats. In this view, ideas cross national boundaries easily, so far-right ideologies endemic in authoritarian states can easily spread to the United States.⁹⁸ Authoritarian states violate human rights, invoke ethnonationalist ideas, and exacerbate economic inequality as they attempt to stay in power.⁹⁹ Aggrieved populations and unstable institutions in turn increase the likelihood of civil conflict that can spill over borders. Moreover, authoritarian states coerce democratic states, resort to force when coercion fails, and interfere in democratic elections.¹⁰⁰ Progressives therefore believe that authoritarian states increase the likelihood of conflict both within and between countries and directly threaten U.S. democratic institutions.¹⁰¹

For progressives, threats stemming from authoritarianism, economic inequality, and climate change are particularly pernicious because they are interrelated. For example, inequality between the Global North and the Global South undermines the trust needed for collective action on problems like climate change.¹⁰² Progressives also view inequality and authoritarianism as linked; authoritarianism is only stable in an unequal society where a small number of elites control and manage resources.¹⁰³ Moreover, authoritarian influence in global economic institutions exacerbates inequality in both authoritarian states and internationally.¹⁰⁴

Although progressives have expansive goals, they do not endorse using military tools to achieve them.¹⁰⁵ First, progressives do not believe that the most urgent threats facing the United States (e.g., climate change, economic inequality, and the rise of authoritarianism) have military solutions.¹⁰⁶ Second, progressives believe that deep engagement diverts resources to the military that should instead be used to promote equality in the United States. Third, like conservatives, they hold that militarism undermines democracy at home.¹⁰⁷ Fourth, progressives believe that U.S. military tools hinder rather than advance U.S. interests abroad.¹⁰⁸ For example, they agree with realists that many military tools (e.g., a forward military presence, arms sales) can threaten rivals and increase the risk of conflict.¹⁰⁹ The United States fuels violence in the Middle East by providing arms and other resources to authoritarian states that abuse their own people or engage in local conflicts (e.g., Saudi Arabia's involvement in Yemen).¹¹⁰ Using the U.S. military to shape events abroad can also morph into imperialism, which progressives view as a form of authoritarianism.¹¹¹ Military competition with states such as China limits the prospects for cooperation on climate change.¹¹² To top it all off, the United States maintains a military footprint that directly damages the environment.¹¹³

Unlike other restrainers, progressives do not see a world of relative security for the United States. Instead, progressives see a world where threats from authoritarianism and inequality abound and can affect the U.S. homeland.¹¹⁴ Most importantly, progressives argue that climate change is an existential threat to humanity.¹¹⁵ As a result, they want policymakers to respond with the same urgency to both military threats and climate change. For example, progressives endorse using diplomatic and economic tools to combat climate change, such as providing aid to help build greener infrastructure in developing nations¹¹⁶ and joining international institutions to find global solutions.¹¹⁷ These restrainers want to reduce the U.S. military footprint to curb emissions.¹¹⁸ Some progressives go further, advocating to restrict access to U.S. markets for those nations and corporations that do not make meaningful progress on combating climate change.¹¹⁹

Progressives view China and Russia as threats more because of their authoritarianism than because of their military power.¹²⁰ Progressives fear that China will continue to coerce other states in East Asia, especially U.S. democratic allies.¹²¹ Progressives also view China's Belt and Road Initiative as exploitative, granting the authoritarian state influence across the globe.¹²² Progressives are concerned that the People's Republic of China abuses human rights, including repressing the Uyghur population.¹²³ Russia is a stark example of progressives’ concerns about authoritarianism. The 2022 invasion of Ukraine demonstrated Russia's willingness to conduct a large-scale military attack on a democratic nation. Progressives also point to Russian election interference and misinformation as a major threat to the United States, its allies, and states vulnerable to democratic backsliding.¹²⁴

Progressives are split, however, on how to address threats from authoritarian powers. These policy disagreements result from differing views on the costs and benefits of relying on military tools such as alliances and on economic tools. Two camps, in particular, have emerged: “progressive pragmatists” and “anti-hegemonists” (so named because they deeply oppose U.S. military hegemony).¹²⁵

Progressive pragmatists view inequality and corruption as root causes of authoritarianism, so they focus on economic tools to address interrelated threats.¹²⁶ For example, they want to wield U.S. influence in international institutions such as the International Monetary Fund and the World Bank to clamp down on the corruption that keeps authoritarian elites in power and hinders economic equality.¹²⁷ Progressive pragmatists also support using economic sanctions against authoritarian states and greater economic decoupling.¹²⁸ Relatedly, they want to close tax havens in order to prevent authoritarian elites from using them to shield their money from potential economic sanctions.¹²⁹

Compared with other progressives, progressive pragmatists are more comfortable using military engagement to counter the threat from authoritarian powers. Progressive pragmatists agree with deep engagers that allies tend to restrain one another from using force. In this view, alliances promote peace because the United States encourages its allies to find non-military solutions (and, importantly, vice versa).¹³⁰ These progressives also argue that alliances foster political and economic relationships that help democracies support one another in countering authoritarian threats at home and abroad.¹³¹ Although progressive pragmatists worry about the negative effects of alliances and other military tools, they think that these costs are worth paying to defend democracies from authoritarian influence and aggression. In this sense, compared with other restrainers, progressive pragmatists have more in common with deep engagers. In fact, some progressive pragmatists do not identify with the restraint label, even though they advocate a less militarized approach to U.S. grand strategy.¹³²

Still, the views of progressive pragmatists and deep engagers only partially overlap on how the United States should use economic and military tools.¹³³ Progressive pragmatists seek a balance of power in key regions, whereas deep engagers seek U.S. military dominance.¹³⁴ Progressive pragmatists do not want the United States to be the primary security provider in other regions. Rather, they view the United States and its allies as equal partners.¹³⁵ Moreover, progressives pragmatists are uneasy about close relations with non-democracies, arguing that the United States should reduce support for such states.¹³⁶ In contrast to deep engagers, progressive pragmatists want the United States to reduce defense spending and its forward military presence.¹³⁷ At the same time, some progressive pragmatists acknowledge the tension in their position: Without sufficient forward presence, the United States may be unable to effectively defend its allies—particularly in the Indo-Pacific.¹³⁸

Anti-hegemonists are even less willing than pragmatists to use military tools to counter China and Russia. They place greater weight on the costs and risks of military engagement than pragmatists and are more skeptical of the benefits. For example, anti-hegemonists believe that alliances and U.S. forward military presence do more to provoke than to deter aggression. They also believe that U.S. military support emboldens partners to use force more often and the United States fails to use its leverage to restrain them. They agree with realists that U.S. alliances can threaten U.S. adversaries, increasing the risk of security-motivated conflict.¹³⁹ As a result, alliances—even with other democracies—may make conflict more likely.¹⁴⁰

Anti-hegemonists eschew interfering in other great powers’ domestic politics, believing that tools such as economic sanctions are ineffective.¹⁴¹ Anti-hegemonists are willing to grant spheres of influence to “near peer competitors” to reduce conflicts of interest and improve the chance of cooperation on issues like climate change. They call for eventually terminating or downgrading current U.S. alliances, especially in Europe, and gradually reducing U.S. forward miliary presence globally.¹⁴² Whereas pragmatists support using the military to defend U.S. allies, anti-hegemonists support using force only in self-defense. At the policy level, anti-hegemonists often agree more with realists and conservatives than with pragmatists.¹⁴³

Will realists, conservatives, and progressives remain united around restraint going forward? As the previous sections outline, these groups arrive at restraint from different starting points. It would not be surprising if their policy prescriptions diverge as international conditions change. We find in particular that the renewed salience of great power threats poses a stress test for restrainers and their ability to agree on a set of policies. Whereas opposition to the war on terrorism enabled realists, conservatives, and progressives to converge on restraint in the Middle East, Russia's invasion of Ukraine and especially China's rise have led to disagreements. We focus here on restrainers’ views on the war in Ukraine, the long-term U.S. role in Europe, peacetime policy toward China, and the defense of Taiwan.

Restrainers support President Joe Biden's decision not to have the United States enter into the war in Ukraine as a combatant. Progressive pragmatists also support the administration's policy of providing Ukraine with substantial military and economic aid with few conditions. But most restrainers prefer either adding more conditions to or reducing aid to Ukraine in order to incentivize it to pursue a near-term diplomatic solution to the war.

Realists and conservatives argue that the United States has only limited interests at stake in Ukraine and point to the risks of greater U.S. involvement (e.g., possibility of nuclear escalation or a NATO-Russia war). These restrainers also argue that U.S. and Ukrainian interests are not perfectly aligned and U.S. support makes Ukraine less willing to compromise with Russia to end the conflict. Realists¹⁴⁴ and classical liberals¹⁴⁵ therefore call on the United States to use its influence to encourage the parties to negotiate. Conservative nationalists are especially critical of U.S. support to Ukraine, seeing it as a distraction from solving domestic problems.¹⁴⁶ A final group of conservatives oppose support for Ukraine because they believe that it diverts resources needed to counter China's rise.¹⁴⁷

Progressives, like other restrainers, oppose direct U.S. military involvement in the war in Ukraine.¹⁴⁸ Beyond that, progressives are internally divided because they do not agree on how to balance two competing concerns: a desire to stand in solidarity with a democratizing country under attack by an authoritarian aggressor, and wariness of potentially negative side effects from militarized U.S. policies. Progressive pragmatists emphasize democratic solidarity and therefore depart from other restrainers in their support for the Biden administration's aid policies.¹⁴⁹ Anti-hegemonists decry Russian aggression but criticize sending U.S. military aid to Ukraine. They worry U.S. involvement will prolong and intensify the war, worsening the humanitarian disaster.¹⁵⁰ Anti-hegemonists acknowledge that supporting Ukraine defends progressive values (i.e., democratic solidarity) in the short term. But in the long term, such a stance undermines these values because it further militarizes U.S. foreign policy and diverts funds from U.S. domestic priorities to fuel more global conflicts.¹⁵¹ Therefore, this group prefers the United States reduce or terminate lethal aid to Ukraine, while continuing to offer humanitarian assistance.

Restrainers have been largely united in calls for U.S. retrenchment from Europe in the long term, though progressive pragmatists may not support such a policy in the future, given Russian aggression. Before Russia's full-scale invasion of Ukraine, realists, conservatives, and anti-hegemonist progressives all agreed Russia was weak and NATO allies could check Russia's aggression if they converted their latent power into military capabilities.¹⁵² For these groups, the ongoing war in Ukraine has both further exposed and contributed to Russia's weakness. Therefore, these restrainers argue that over the long term, the United States can largely eliminate its military presence in Europe and encourage greater European autonomy.¹⁵³ In the words of Justin Logan, “Maintaining U.S. domination of the European security scene is a luxury good the United States doesn't need.”¹⁵⁴ Some support the United States either reducing its role in or even completely withdrawing from NATO.¹⁵⁵

Progressive pragmatists and other restrainers appear likely to diverge on postwar policy. Before Russia's 2022 full-scale invasion of Ukraine, progressives were open to some retrenchment. They wanted the United States to remain in NATO but have a more equal partnership with its allies. Progressive pragmatists have not yet written on postwar policy, so we have greater uncertainty about their views for the future. But this group's counter-authoritarian impulses, emphasis on democratic solidarity, and differences with other restrainers on wartime policy suggest they will be hesitant to reduce the U.S. role in Europe.

While most restrainers will probably continue to call for U.S. retrenchment from Europe, they are deeply divided on U.S. strategy in East Asia. These divisions are sharper within groups than between them. Some realists and conservatives support the Biden administration's approach to the region that emphasizes U.S. leadership in balancing China, deepening U.S. commitments, and strengthening the U.S. military presence.¹⁵⁶ Compared with these hard-line conservatives and realists, progressive pragmatists prefer a less militarized approach but still want the United States to maintain its current commitments to regional allies. Within each group, some call for remaining committed to restraint. Anti-hegemonists and many realists and conservatives warn that current U.S. strategy is pushing the United States and China toward a new Cold War. These restrainers would prefer to find ways to resolve some of the conflicts of interest between the United States and China. They are comfortable letting local allies take the lead in managing regional security while the United States continues to monitor China's trajectory.¹⁵⁷

Differences among restrainers are likely to grow. If China becomes more powerful economically, politically, and militarily, concerns about the balance of power or threats to the American way of life could lead more realists and conservatives to support a greater U.S. military role in the region. If China becomes more aggressive toward regional democracies, progressive pragmatists might also advocate for deep engagement. But anti-hegemonists and other realists and conservatives may view deep engagement on China's periphery as even more unsustainable and presenting too great a risk of war with an increasingly powerful adversary. These restrainers may therefore be more willing to limit U.S. aims in the region as China's power grows.

If China were to attack Taiwan, restrainers are divided on whether the United States should intervene. Anti-hegemonists and most realist and conservative restrainers oppose direct U.S. involvement in a conflict over Taiwan, arguing that the United States does not have sufficient interests at stake to justify the costs of a high-intensity great power war and the associated risks of nuclear escalation.¹⁵⁸ Yet those realists and conservatives who already want to contain China are willing to see the United States fight for Taiwan's independence.¹⁵⁹ Progressive pragmatists’ views echo but do not perfectly mirror disagreements they have with other restrainers on Ukraine. Some progressives who oppose U.S. military intervention to support Ukraine are open to (but noncommittal about) using force to defend Taiwan.¹⁶⁰ Two possible reasons for this apparent contradiction are that Taiwan is a more established democracy, and the United States has longer-standing security ties with Taiwan than with Ukraine.

For more than twenty years, realists, conservatives, and progressives have converged in a big tent to oppose deep engagement. What are the prospects for this camp to affect the direction of U.S. grand strategy in the future? Ultimately, we are uncertain. On the one hand, Russian aggression and China's growing power could lead some of today's restrainers to become deep engagers, weakening restraint's political influence. On the other hand, U.S. fiscal challenges, crises in multiple regions, and a distribution of power shifting away from the United States could make deep engagement appear too risky or costly, potentially drawing more adherents to restraint.

Restrainers are the first to admit they are a minority in the grand strategy debate. Deep engagement emerged during the Cold War, when the United States’ security commitments were arguably necessary for containing the Soviet threat. Over time, the strategy became entrenched as the foreign policy establishment internalized its core premises.¹⁶¹ The end of the Cold War did usher in a debate about the direction of U.S. grand strategy, but unipolarity meant the costs and risks of deep engagement were tolerable. The operative question was how much more ambitious the United States should be. In this context, restrainers struggled to significantly shift U.S. grand strategy. Russia's recent aggression has made the case for restraint in Europe more difficult. Those who remain committed to restraint in East Asia face an uphill battle against the bipartisan consensus on a hard-line China policy. They may find their numbers dwindling if China's power and aggression toward democracies in the region continue to grow. Foreign and domestic policy differences among restrainers will probably continue to compound these challenges to building and sustaining a restraint coalition.

But some geopolitical and domestic developments could improve restrainers’ prospects for influencing U.S. policy. Indeed, the strategic landscape is changing in ways that could cause some restrainers to double down and attract new converts to their cause. The shift in power away from the United States and intensified great power competition could lead more Americans to view deep engagement as too risky. Mounting domestic and fiscal challenges may also cause some to view deep engagement as unsustainable, forcing hard choices about international commitments, especially in Europe and the Middle East. In this context, the politically diverse arguments in favor of restraint could facilitate coalition building. It is impossible to predict how these countervailing considerations will affect restrainers’ future political influence.

What we can say is that restraint is likely to remain a pole in the grand strategy debate. Furthermore, restrainers are likely to find more agreement on strategy in Europe and the Middle East than in East Asia.¹⁶² Restrainers’ stated policy positions and the underlying logics suggest that most restrainers will continue to call for retrenchment from these two regions. Some progressives will remain wary of the Russia threat and hence reluctant to retrench from Europe at first, but most restrainers appear committed to a U.S. drawdown in the region. The urgency of these calls is likely to grow, especially from those restrainers most concerned about China's rise who want to focus U.S. resources on a strategy of deep engagement in East Asia. The arguments that the United States is fundamentally secure, the pursuit of primacy is self-defeating, or U.S. militarism is ultimately corrosive at home and abroad will keep some committed to restraint in East Asia. While the number of such voices may diminish under some conditions, we expect they will continue to provide a counterpoint to deep engagement at a time of high grand strategic stakes.

The authors thank those restrainers who agreed to be interviewed for the article as well as participants in two workshops on the topic (College Station, Texas, February 2020, and Washington, DC, January 2024). The authors are also grateful to the anonymous reviewers. Garrett Hinck and Rosa Maria Torres at RAND and Benjamin Giltner at the Bush School provided expert assistance. The authors gratefully acknowledge the Charles Koch Foundation and the Stand Together Trust for ongoing financial support to their centers. The interviews conducted for this article were approved by the Institutional Review Board of Texas A&M University (IRB #2022-0574) and by RAND's Human Subjects Protection Committee (2022-N0079).