After the Soviet Union collapsed, Richard Nixon observed that the United States had won the Cold War, but had not yet won the peace. Since then, three American presidents—representing both political parties—have not yet accomplished that task. On the contrary, peace seems increasingly out of reach as threats to U.S. security and prosperity multiply both at the systemic level, where dissatisfied major powers are increasingly challenging the international order, and at the state and substate level, where dissatisfied ethnic, tribal, religious and other groups are destabilizing key countries and even entire regions.
Allison, Graham, and Dmitri K. Simes. "Stumbling to War." National Interest, April 20, 2015.