During its tenure, the Obama administration ensured U.S.-Vietnam military cooperation moved forward rapidly, turning a foe on the Indochina field into a close partner that can operate jointly and think about co-production of weapons. While many attribute the two sides' marvelous advance to common concern over the China threat, little has been said about how the China factor influences this bilateral military relationship. In addressing the latter issue, this paper proceeds at two levels: goal setting and strategic interaction. It is found that the U.S. and Vietnam have divergent goals in military cooperation though both having as key element the need to deal with China. However, it is the strategic interaction with China that determines when the U.S. is willing to move beyond routine and close the gap in goal setting between itself and Vietnam. This explains the evolution of U.S.-Vietnam military cooperation between 2010 and 2016.