Trump’s decision to renege on the nuclear deal was a terrible unforced error, and the process that led to that decision is no less worrisome: Even if Mr. Mattis had wanted to fight for the deal, it is not clear how much he would have been heard. Mr. Bolton, officials said, never convened a high-level meeting of the National Security Council to air the debate [bold mine-DL]. He advised Mr. Trump in smaller sessions, otherwise keeping the door to his West Wing office closed. Mr. Bolton has forged a comfortable relationship with the president, several people said, channeling his “America...