Donald Trump*s desire to put ※America First§ has fostered new disputes between the United States and its allies. In Asia, old rivalries are also roaring back.

Ties between Japan and South Korea 〞 two of Washington*s closest security partners 〞 have arguably turned their most hostile in more than half a century over a series of diplomatic disputes. Now, there are signs that the feud, fueled by disagreements over Japan*s colonization of the Korean Peninsula decades ago, is beginning to damage their economic and military relations.

During previous nationalistic flare-ups, U.S. administrations normally intervened to make sure such grudges did not spin out of control. Not any more.