East Asian military security is of overarching importance in the economic integration
and prosperity in this region. This study analyzes how South Korea and Japan consider
the U.S. as a military ally in the context of the China-North Korea alliance by using the
iterative Seemingly Unrelated Regression(SUR) method in estimating defense goods
demand functions. The findings are that Japan considered the U.S. to be a closer ally
than the U.S. did during 2000-2005 and South Korea may regard the U.S. as a closer
ally than vice versa. The U.S. regards Japan as a closer ally than Korea. South Korea's
demand for defense goods has not been increased by the threat from the China-North
Korea alliance but American and Japanese demand has recently been increased by the
threat, implying that South Korea has not regarded the China-North Korea alliance as a
significant threat whereas that Japan and the U.S. have recognized the military alliance
as a serious one