Days before he officially becomes a U.S. senator, Mitt Romney took to the Washington Post to fire a shot across President Trump’s bow, saying Mr. Trump had made a “deep descent” in December and is hurting the national character. In an op-ed column published online Tuesday evening, Mr. Romney, now a Republican senator-elect for Utah, came down hardest on recent moves in foreign policy and Cabinet positions related to that. “After he became the nominee, I hoped his campaign would refrain from resentment and name-calling. It did not. When he won the election, I hoped he would rise to the...