The world's two largest economies should reinvigorate their collaborative use of "soft power" to influence other countries as they approach a milestone year in their security alliance, participants said at a recent symposium that included key U.S. commentators on diplomacy.

The United States and Japan, marking the 50th anniversary of their security alliance next year, should reassess their noncoercive tactics to tackle urgent global issues such as climate change and maintaining stability in East Asia, Joseph Nye, a former assistant secretary of defense and now an international relations professor at Harvard University, said in a videotaped message to the June 12 event.

The phrase soft power, coined by Nye in 1990, means a nation's ability to obtain desired outcomes through the attraction of its culture, technology or policies, rather than by coercion, or "hard power."