From the Christian Science Monitor‘s blog:
Each nation is a democracy. They are already allies individually with the United States. Each trains with the American military separately in joint naval exercises.
Most of all they are close neighbors in the tough neighbor of Northeast Asia that includes North Korea, China, and Russia. The threat of North Korea someday launching a nuclear-tipped missile toward either country should have had the effect of drawing Japan and South Korea closer.
But as much as the United States wants the two countries to cozy up, history has long kept them apart. (Link)
A contributor and editor at the blog War Is Boring, Kyle Mizokami started Japan Security Watch in 2010 to further understand Japan's defenses and security policy.
Kyle Mizokami has 536 post(s) on Japan Security Watch