“We have no eternal allies, and we have no perpetual enemies.” The words of the 19thcentury British statesman Lord Palmerstone seem to resonate in 21st-century Asia. For example, China and the United States fought against each other during the Korean War, but now the two great powers are exploring a new style of constructive strategic partnership. Japan and Vietnam fought against the United States in the last century, but they too are now strong allies and major strategic partners of the United States.