U.S. President Barack Obama, center, arrives for the East Asian Summit Plenary Session at the Peace Palace in Phnom Penh, Cambodia, Tuesday, Nov. 20, 2012. Walking in front of President Obama is Chinese Premier Wen Jiabao. (AP Photo/Carolyn Kaster)

Photo by: Carolyn Kaster

U.S. President Barack Obama, center, arrives for the East Asian Summit Plenary Session at the Peace Palace in Phnom Penh, Cambodia, Tuesday, Nov. 20, 2012. Walking in front of President Obama is Chinese Premier Wen Jiabao. (AP Photo/Carolyn Kaster)