Olympic Détente Upends U.S. Strategy on North Korea

South Koreans holding “unification flags” at a hockey game between South Korea and North Korea in 2017. In addition to marching together, the two Koreas will field a joint women’s hockey team at the Games, which begin Feb. 9 in Pyeongchang, South Korea.SEOUL, South Korea — North and South Korea reached an agreement Wednesday for their athletes to march together under one flag at the opening ceremony of the Winter Olympics next month, a powerful gesture of reconciliation that further complicates President Trump’s strategy for dealing with the nuclear-armed regime of Kim Jong-un.

South Korea, the host of the games, said it hoped a partnership in sports could contribute to a political thaw…