WASHINGTON -- Despite efforts during last month's summit between South Korean President Roh Moo Hyun and President George W. Bush in Washington to speak with "one voice" about the health of the alliance and to improve policy coordination toward North Korea, the summit saw the emergence of a potentially serious new area of divergence between American and South Korean allies: the role and future of Japan.

South Korean criticisms of Japan are particularly sensitive for the Bush administration in view of the perception in Washington that Prime Minister Junichiro Koizumi has been one of America's most faithful and consistent supporters following 9/11 -- providing logistic support in Afghanistan and sending Japan's Self-Defense Forces to Iraq. But where Washington perceives loyalty and a Japan that is stepping up to the plate as a partner in achieving global stability, Seoul sees a rightward shift in Japanese politics and the prospect of Japan's renewed remilitarization.

The emergence of Korean and Chinese tensions with Japan over Japan's textbooks, renewed tensions over the disputed Tok-do/Takeshima islands, and Koizumi's visits to Yasukuni Shrine, Japan's memorial to its war dead, are background issues that have recently pushed hot buttons in Seoul and Beijing, but they have barely registered as dire matters for American policymakers focused on Japan's near-term strategic cooperation in the global war on terrorism and the longer-term need to balance against a rising China.