"You don't have unanimity on the part of ASEAN behind the scenes to say this is our top-drawer issue," he said. "There are some who think it's crucial. And there are others who say it's not as important, and so the longer it drags out, the easier it is for us to avoid a day of reckoning with China."

As part of its so-called "Asia Pivot," the United States is boosting military and commercial activity, which contributes to stability, says Burmese Foreign Minister Wunna Maung Lwin.

"We appreciate very much the United States government on a strong, secure, and prosperous Southeast Asia." Lwin said. "The positive stance of the Untied States has promoted peace, stability, and prosperity."

As part of talks on the sidelines of the United Nations General Assembly, Kerry met with Foreign Minister Marty Natalegawa of Indonesia. Jakarta is central to resolving South China Sea disputes, says Auslin.

"From the eastern Indian Ocean to the Western Pacific, you don't get more strategically positioned than that in terms of the sets of concerns that it has to deal with," he said. "Whether it's piracy, whether it's proliferation, narcotics trafficking, the rise of the Chinese navy and military or the like, Indonesia is the centrally located country."

Washington is selling Jakarta eight Apache attack helicopters for $500 million, an upgrade that Indonesia says reflects greater military investments across the region.