Ian Buruma a very notable author in regards to Asian affairs had this to say in the New Yorker about the US military presence in South Korea and Japan:
The problem is that the existing order, put in place by the United States after the Second World War, might be exactly what hampers efforts to thicken that web. In a sense, America is experiencing the dilemmas typical of an empire in its twilight years. Imperial powers in the middle of the twentieth century used to argue that they couldn’t withdraw as long as their colonial subjects were not ready to rule themselves. But, as the British Prime Minister Harold Macmillan once explained to a rather baffled William F. Buckley, Jr., the continuance of colonial rule would not make them more ready. If the United States were to give up its policing duties in Asia too quickly, chaos might ensue. The longer its Asian allies remain dependent on U.S. military protection, however, the harder it will be for them to take care of themselves.
The most desirable way to balance the rising power of China would be the creation of a regional defense alliance stretching from South Korea to Burma. Japan, as the leading economic and military power, would be the logical choice to lead such a coalition. This would mean, in an ideal world, that Japan should revise its pacifist constitution after a national debate, led not by a government of chauvinistic revanchists but by a more liberal administration. But we do not live in an ideal world. Abe’s revisionism (he has currently set 2020 as a deadline for the amended constitution) is unlikely to achieve its aims in Japan. Most Japanese are no keener than most Germans to play a major military role once again. And as long as Japanese leaders insist on whitewashing their country’s recent past they will never persuade other countries in the region to trust them.
This is the status quo that dependence on the United States has frozen into place. As much as Abe’s government wishes to remain under the American military umbrella, the American postwar order, including the pacifist constitution, still inflames right-wing resentment. Yet Washington, and especially the Pentagon, which shapes much of U.S. policy in East Asia, has consistently supported conservative governments in Japan, seeing them as an anti-Communist bulwark. Meanwhile, as long as the United States is there to keep the peace, the governments of Japan and South Korea will continue to snipe at each other, instead of strengthening their alliance. [The New Yorker]
You can read much more at the link, but Buruma’s comments are based on a book he reviewed titled “Avoiding War with China: Two Nations, One World” by Amitai Etzioni. This analysis seems pretty accurate, does anyone disagree with it?