Vietnam's steadily improving relationship with the US provoked the ire of China over the summer after US Secretary of State Hilary Clinton told a regional security forum in Hanoi that the peaceful resolution of disputes over hotly-contested islands in the South China Sea was in America's national interest.
Barack Obama will re-iterate this view at a meeting with leaders from the Association of Southeast Asian Nations (ASEAN) on Friday, according to an AP report, reassuring Vietnam and the other ASEAN countries that claim some of the Spratly and Paracel islands that the US will not abandon them to China's whim.
Where old rivalries run deep, it often appears that diplomacy is a zero sum game, with Vietnam's growing military and diplomatic cooperation with the US seemingly bound to damage relations with China.
But Vietnam's foreign minister, who I interviewed for the Financial Times recently, believes Vietnam can move closer to both China and the US without alienating either side.
"To enhance relations with the US does not mean we want to be against China," Pham Gia Khiem, who is also a deputy prime minister, told me. "Vietnam has enjoyed good military co-operation with many countries, including China, the Southeast Asian nations and the US. The goal of our military cooperation is to keep and enhance peace and stability."
He welcomed Hilary Clinton's recent comments on the South China Sea dispute but insisted that Vietnam did not want to bring in America as a bulwark against Chinese might.
"We don’t want to engage any country to be against a third country – that’s not our policy."
But he did accept that Vietnam, which has been trying to extend military cooperation with China as well as the US and other Southeast Asian nations, needed to work hard to erode mutual suspicion.
"In relations between Vietnam and other countries, the building of confidence is the most important thing. Confidence building helps avoid scepticism. Vietnam and China want to develop a comprehensive strategic partnership and the foundation is confidence building as it is a good way to reduce doubt."