In 2000, 19 months before Sept. 11, 2001, Donald Trump wrote extensively of the terrorism threat the United States was facing. Trump, who at the time was considering a presidential bid on the Reform Party ticket, went so far as to say that an attack on a major U.S. city was not just a probability, but an inevitability. “I really am convinced we’re in danger of the sort of terrorist attacks that will make the bombing of the Trade Center look like kids playing with firecrackers,” wrote Trump in his 2000 book, The America We Deserve. “No sensible analyst rejects...