Earlier this month 50 senior Republican national security officials signed a letter arguing that Donald Trump “lacks the character, values and experience” to lead the United States. “We are convinced”, they wrote, “he would be a dangerous president”. We want to know if they are right. Our expert witnesses are: Timothy O’Brien, author of The Art of Being The Donald; Peter Feaman, Florida representative for the Republican National Committee; Daniel Drezner, professor of international politics at Tufts; and Elaine Kamarck from the Brookings Institution, an expert on presidential power and its limits. (Photo: Republican presidential candidate Donald Trump speaks during an event at Trump SoHo Hotel, 2016, New York. Credit: Getty Images)