Despite efforts to forge deeper ties with China to make East Asia more stable, Beijing's declaration of a maritime air defence zone has escalated its territorial dispute with US ally Japan. The US responded by flying B-52 bombers through the zone on a training mission yesterday without informing Beijing.
Analysts say the risk of a military clash between the Asian powers has gone up a notch a serious concern for the US because its treaty obligations mean it could be drawn in to help Japan.
That complicates the strategic picture for the Obama administration as it looks to advance its so-called pivot to Asia and strengthen not just its own alliances, but get its partners in the region to collaborate more.
"The region is moving in a very problematic direction," said Evans Revere, a former senior US diplomat and East Asia specialist. "That's the result of territorial disputes, historical issues, long-standing rivalries and the inability of countries to put history behind them and move forward in improving relations."
Unlike Iran, North Korea already has a nuclear bomb, and there's worrying evidence it is pressing ahead with weapons development.
Vice President Joe Biden will broach these issues when he travels to Japan, China and South Korea next week a trip to demonstrate that the top level of the administration remains focused on Asia.
