When a country faces a greedy state, the standard policy prescription is to deter it. In the case of China and Russia, then, the United States should strengthen its military advantages, communicate its resolve, and pursue economic and political policies to weaken these adversaries. When a country faces an insecure state, by contrast, the solution is not so simple. In that case, policymakers must reckon with a key concept in international relations theory: the security dilemma.