Ex-national security adviser John Bolton issued harsh remarks against his former boss and the leading 2024 Republican presidential candidate, saying that the US will likely withdraw from Nato if Donald Trump wins the election. In an interview with the Hill on Thursday, Bolton criticized the former president’s foreign policy after an op-ed he wrote earlier this week called Trump’s behavior “erratic, irrational and unconstrained”. “Donald Trump doesn’t really have a philosophy, as we understand it in political terms,” Bolton said. “He doesn’t think in policy directions when he makes decisions, certainly in the national security space.” Bolton, who was Trump’s national security adviser from April 2018 to September 2019, also lambasted Trump for his foreign policy legacy with regard to the alliance, saying in the interview: “He threatened the existence of Nato, and I think in a second Trump term, we’d almost certainly withdraw from Nato.” He also criticized Republicans who have praised Trump for his foreign policy positions. He said: “Those who make these claims about what Trump did in his first term don’t really understand how we got to the places we did. Because many of the things they now give Trump credit for, he wanted to go in the opposite direction.” In Bolton’s op-ed published on Tuesday, he said Trump “disdains knowledge” and accused him of “seeing relations between the United States and foreign lands, especially our adversaries, predominantly as matters of personality”. “Foreign leaders, friend or foe, are far more likely see him as ignorant, inexperienced, braggadocious, longing to be one of the big boys and eminently susceptible to flattery,” Bolton wrote. “These characteristics were a constant source of risk in Trump’s first term, and would be again in a second term.” Bolton condemned Trump for his decision-making, saying: “Beyond acting on inadequate information, reflection or discussion, Trump is also feckless even after making decisions. When things go wrong, or when he simply changes his mind subsequently (a common occurrence), he invariably tries to distance himself from his own decision, fearing negative media coverage or political criticism.” Following his firing in 2019, Bolton published a book, The Room Where It Happened, in which he strongly criticized Trump’s leadership. Earlier this year, Bolton called Trump’s 2024 presidential bid “poison” to the Republican party. Since March, Trump has been criminally charged in connection with hush money payments to adult film actor Stormy Daniels, with his hoarding of classified documents at his Florida resort, and with allegedly having a hand in illegal efforts to overturn his defeat to Joe Biden in the 2020 presidential race. Trump has pleaded not guilty to all charges filed against him.