After a decade and a half of counterinsurgency operations in Iraq and Afghanistan, U.S. policymakers want to change their approach to COIN by providing aid and advice to local governments rather than directly intervening with U.S. forces. Both this strategy and U.S. counterinsurgency doctrine in general, however, do not acknowledge the difficulty of convincing clients to follow U.S. COIN prescriptions. The historical record suggests that, despite a shared aim of defeating an insurgency, the United States and its local partners have had significantly different goals, priorities, and interests with respect to the conduct of their counterinsurgency campaigns. Consequently, a key focus of attention in any future counterinsurgency assistance effort should be on shaping the client state's strategy and behavior. Although it is tempting to think that providing significant amounts of aid will generate the leverage necessary to affect a client's behavior and policies, the U.S. experience in assisting the government of El Salvador in that country's twelve-year civil war demonstrates that influence is more likely to flow from tight conditions on aid than from boundless generosity.