Unless the U.S. military does something to stop it (and maybe even then), North Korea is going to become a full-fledged nuclear power, a fact that is stressing the U.S. alliance structure in Northeast Asia. Whether the U.S. decides to attack or learn to live with it, its decision could undermine America’s credibility with its two stalwart partners in the region, Japan and South Korea. And with North Korea on the path to being able to strike the U.S. mainland, the question is looming larger whether the U.S. can be trusted to respond to an attack on Japan or South Korea even when doing so puts U.S. cities at risk.
The U.S. alliance structure could evolve a number of ways over the coming decades. But when examining the degree to which Japan and South Korea will continue to put their faith in U.S. security guarantees – or whether each country could fully break from the U.S. alliance – there’s one inescapable variable: the willingness of either country to continu