In February 2016, Donald Trump scandalized Republican Party elites at a CNN town hall event in Columbus, Ohio, when he dared to call George W. Bush’s invasion of Iraq “a big fat mistake” and “the worst decision any one has made, any president has made, in the history of this country.” Trump’s assertion infuriated GOP insiders not because it was clearly mistaken or even easily disputable, but because it was all too true. A glance at the titles of major books on America in the Middle East written by authors across the political spectrum—Fiasco, Grand Delusion, Losing the Long Game,...