Because the post-Cold War world is as unpredictable and dangerous as ever, alliances and international cooperative efforts are crucial to maintaining security.
Regional aggressors are just one part of the threat scenario.
Cooperative security arrangements enable the United States and its allies to provide the stability necessary for democracy-building, economic progress, and the orderly resolution of conflicts. The cornerstone of this stability is equitable sharing of mutual security responsibilities. For example, in the Asia-Pacific region, Japan and the Republic of Korea are the top two U.S. security allies. These forces are a tangible expression of vital American interests in Asia and the ability to defend those interests. By supporting the presence of these forces, Japan and South Korea declare their commitment to maintaining defense and deterrence in the region.