President Barack Obama leaves on a diplomatic trip to Asia on Wednesday. First stop, Japan. Then, on to other allies in the region—South Korea, the Phillippines and Malaysia. He’ll be talking economics, and trade, and cooperation—to try to signal to these Pacific Rim allies that the U.S. is serious about its stated aim to ‘pivot’ toward them. Analysts say the President needs to convince them that the U.S. will back them up in their regional competition with rivals like China, as tensions have heated up over conflicts in the East China Sea.