A notice calls the people the U.S. military recently killed on suspicion of drug smuggling in the Caribbean Sea “unlawful combatants.”President Trump has decided that the United States is engaged in a formal “armed conflict” with drug cartels his team has labeled terrorist organizations and that suspected smugglers for such groups are “unlawful combatants,” the administration said in a confidential notice to Congress this week. The notice was sent to several congressional committees and obtained by The New York Times. It adds new detail to the administration’s thinly articulated legal rationale for why three U.S. military strikes the president ordered...