Anyone who desires territorial concessions form a U.S. ally realizes that they have until January, 2017 to make it happen.
That idea is predicated upon the assumption that a president as bad or worse than Obama won’t be elected.
Consider Jimmy Carter (Iran, Panama Canal) and Bill Clinton (selling out to China) came before Obama.
But I was under the impression they're more likely to attach Taiwan and not Japan, but what do I know?