International relations scholarship overwhelmingly expects that relatively rising states will threaten and challenge declining great powers. In practice, however, rising states can also cooperate with and support declining powers. What explains the rising state's choice of policy? When do rising states support or prey on declining great powers, and why do such strategies vary across time and space? The answer depends on the rising state's broader strategic calculations. All things being equal, a rising state will generally support a declining power when the latter can be used to offset threats from other great powers that can harm the rising state's security. Conversely, when using a declining state to offset such challenges is not a plausible option, the rising state is likely to pursue a predation strategy. The level of assertiveness of support or predation, meanwhile, depends on the declining power's military posture: the stronger the declining state is militarily, the less assertive the rising state tends to be. A review of the strategies adopted by two relatively rising powers, the United States and the Soviet Union, toward a declining Great Britain after 1945, and of a rising United States vis-à-vis a declining Soviet Union in the late Cold War, illustrates how this argument outperforms explanations that focus instead on the importance of economic interdependence and ideology.

Did the United States promise the Soviet Union during the 1990 negotiations on German reunification that NATO would not expand into Eastern Europe? Since the end of the Cold War, an array of Soviet/Russian policymakers have charged that NATO expansion violates a U.S. pledge advanced in 1990; in contrast, Western scholars and political leaders dispute that the United States made any such commitment. Recently declassified U.S. government documents provide evidence supporting the Soviet/Russian position. Although no non-expansion pledge was ever codified, U.S. policymakers presented their Soviet counterparts with implicit and informal assurances in 1990 strongly suggesting that NATO would not expand in post–Cold War Europe if the Soviet Union consented to German reunification. The documents also show, however, that the United States used the reunification negotiations to exploit Soviet weaknesses by depicting a mutually acceptable post–Cold War security environment, while actually seeking a system dominated by the United States and opening the door to NATO's eastward expansion. The results of this analysis carry implications for international relations theory, diplomatic history, and current U.S.-Russian relations.

The United States and its Persian Gulf allies have been increasingly concerned with the growing size and complexity of Iran's ballistic missile programs. At a time when the United States and its allies remain locked in a standoff with Iran over the latter's nuclear program, states around the Persian Gulf fear that Iran would retaliate for an attack on its nuclear program by launching missiles at regional oil installations and other strategic targets. An examination of the threat posed by Iran's missiles to Saudi Arabian oil installations, based on an assessment of Iran's missile capabilities, a detailed analysis of Saudi Arabian oil infrastructure, and a simulated missile campaign against the network using known Iranian weapons, finds no evidence of a significant Iranian missile threat to Saudi infrastructure. These findings cast doubt on one aspect of the Iranian threat to Persian Gulf oil while offering an analytic framework for understanding developments in the Iranian missile arsenal and the vulnerability of oil infrastructure to conventional attack.