President Donald Trump on Thursday ruled out using a nuclear weapon in the war with Iran. He told reporters in the Oval Office that the United States has already greatly weakened the Islamic Republic with conventional weapons, declaring that “a nuclear weapon should never be allowed to be used by anybody.” PBS NewsHour correspondent Liz Landers asked the president whether nuclear weapons might be used in the war, which the president said was a “stupid” question. “Why would I use a nuclear weapon when we’ve totally and in a very conventional way decimated them without it?” Trump said. “I wouldn’t use it.”...