When U.S. President George W. Bush and Japanese Prime Minister Koizumi Junichiro took a friendly stroll through the quiet grounds of Kyoto's Imperial Palace last November, it was easy to assume that things just couldn't have been better between the two countries. Yes, there was the issue of U.S. beef, which Japan had banned in 2003 after mad-cow disease was discovered in U.S. cattle. But bilateral trade issues have always taken a back seat to the U.S.-Japan Security Treaty, and it was clear Bush and Koizumi were in Kyoto to celebrate an agreement, signed in October, that would be the first major realignment of U.S. forces in Japan since the end of the Cold War.