Under the Biden administration, the militaries of the United States and Vietnam are expected to cooperate even more closely. The US has already provided drones, radar equipment and warships — all to build up Vietnam’s navy and slow down China’s domination of the South China Sea. The US will increasingly send its own warships and fighter jets into the sea but the US also seeks a local ally. As The World’s Patrick Winn reports, Vietnam has the bravado to step in.