Problems Pile up in Asia for US Policymakers While the Obama administration is making diplomatic progress on some of the Mideast's thorniest security issues, problems are piling up in Asia, a region that President Barack Obama had wanted to play a bigger part in American foreign policy. Despite efforts to forge deeper ties with China to make East Asia more stable, Beijing's declaration of a maritime air defense zone has escalated its territorial dispute with U.S. ally Japan. The U.S. responded by flying B-52 bombers through the zone on a training mission Tuesday 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 U.S. because its treaty obligations mean it could be drawn in to help Japan. Meantime, relations between America's core allies in the region, Japan and South Korea, have deteriorated. South Korea is bitter over Japan's attitude toward its colonial past and wants more contrition from Tokyo for Japan's use of Korean sex slaves in World War II. 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 U.S. 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. Adding to this witches' brew of bickering in the region, Washington is grappling with the threat posed by an unpredictable North Korea. The deal the U.S. orchestrated with Iran to temporarily freeze its nuclear program, despite three decades of animosity, is a stark reminder of the impasse in negotiations with Pyongyang. Unlike Iran, North Korea already has a nuclear bomb, and there's worrying evidence it is pressing ahead with weapons development. Analysts expect Vice President Joe Biden to 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. Secretary of State John Kerry hasn't neglected the region, but his primary focus is on the Mideast and is likely to remain that way as he strives for the distant goals of an end to Syria's civil war, peace between Israelis and Palestinians, and a comprehensive nuclear agreement with Iran after the current pact expires in six months. U.S. domestic woes have contributed to a narrative that Asia is a secondary concern to the administration. Obama was forced to cancel a four-nation trip to the region in October because of a partial U.S. government shutdown and threat of a debt default. He'll travel to Asia in April instead. Obama made Asia a foreign policy priority when he took power in 2009 and has been particularly active in engaging China. Not known for the personal touch with foreign leaders, Obama sought to cultivate a relationship with new Chinese leader Xi Jinping when he met him in June at a California resort. That's part of a strategy to promote cooperation between the world's two largest economies and prevent their rivalry in the Asia-Pacific from spawning conflict.