Turkish jets struck a Kurdish base near the Iraq-Syria border late Monday night, the first grim fruits of President Trump’s decision to order US forces out of the way — a decision we fear Trump will come to regret. We’ll grant that the president is delivering on a campaign promise here: Like most Americans, he doesn’t want this nation serving as the world’s policeman; other countries should share more of the burden when it comes to both troops and money. Or, as he tweeted Monday, “it is time for us to get out of these ridiculous Endless Wars.” He has...