Maj. Gen. Qasem Soleimani was an implacable enemy of the United States who was responsible for hundreds of American deaths, as well as countless atrocities in Iraq, Syria, Lebanon and elsewhere. His death in a drone strike was being cheered Friday by U.S. allies and progressive forces across the region, from Israelis and Saudis to the pro-reform demonstrators of Beirut and Baghdad. That, however, doesn’t mean that President Trump’s decision to assassinate him was wise, or that it will ultimately benefit U.S. interests.

The consequences of the strike are unpredictable, but there is no denying the risk that the United States will be pulled more deeply into the Middle East and its conflicts. Having made clear that he wants to pull the nation out of those conflicts, and having said as recently as Tuesday that he wanted peace with Iran, Mr. Trump has committed an act of escalation and now is deploying more than 4,000 additional troops to Kuwait as a hedge against Iranian counterstrikes.