In the 18-page foreword, "The Room Where It Will Happen Again," Bolton worries Trump could pull the U.S. out of NATO, abuse power to exact retribution on political rivals and trigger a constitutional crisis. Zoom in: Bolton reserved his most damning predictions for foreign policy. He wrote that Trump could: Throw Ukraine under the bus to favor Russian President Vladimir Putin. Endanger Taiwan's independence and embolden China. Seek a bad deal with Iran driven by his desire to prove himself a master negotiator. " It is a close contest between Putin and Xi Jinping, who would be happiest.