The quality of the U.S. military has improved steadily since the end of the Cold War, but technological and managerial advancements cannot compensate for the inadequate size of the American armed forces. The post–Cold War years saw a shift from the Westphalian, state-ordered world to one where Western states are at war with transnational, substate terrorist groups. This requires adjustments in the American military establishment. Improvements in quality must be matched by an increase in quantity in order to meet U.S. security needs. As interventions in Afghanistan and Iraq have proven, a minimalist force may be sufficient to win a war, but where nation-building is required, it will find it difficult to win the peace.