A former ranking U.S. official expressed concerns in a recent interview over the current situation surrounding the U.S.-Japan security alliance, including China's emergence.

Kurt Campbell, a former defense deputy assistant secretary for East Asia and Pacific affairs, said the administration of President George W. Bush lacks high-level commitment in moving forward with the realignment of the U.S. military in Japan, including the stalled plan to relocate the Futenma Air Station in Okinawa.

Against this backdrop, Campbell said he is "much more worried about China-Japan relations" than the Taiwan issue and even developments over North Korea, stressing it has "the potential to trigger a misunderstanding" and "could be devastating."