The security environment since the Sept. 11, 2001, terrorist attacks on the United States has clearly demonstrated the limits of the United Nations, or even the U.S. as the world's sole military superpower, to maintain international security. However, like-minded mid-level powers with similar intentions could complement what the U.N. or the U.S. lacks, effectively generating sufficient clout to stabilize the global security environment.

Japan, Australia, Germany and Canada might be just such powers. They share common values as free and democratic countries. Moreover, they are nonnuclear powers with no permanent seats in the U.N. Security Council. All are longtime allies of the U.S. In fact, over recent years these countries have already had many opportunities to demonstrate their ability and willingness to contribute to international security if called for. They all also share a recognition that global stability directly serves their own national interests.

Nevertheless, subtle differences among these countries may influence their bilateral cooperation or coordination with the U.N. or the U.S. As a result, they must complement each other's advantages, characteristics and interests in order to optimize their role in promoting international security.