Former national security adviser John Bolton, a self-described “lifelong conservative,” said he will not vote for President Trump in November, calling Trump a “danger for the republic” during a televised interview with ABC News that aired Sunday night.

“I hope [history] will remember him as a one-term president who didn’t plunge the country irretrievably into a downward spiral we can’t recall from,” Bolton told ABC News’s Martha Raddatz. “We can get over one term. I have absolute confidence. … Two terms, I’m more troubled about.”

Bolton’s public excoriation of his former boss comes as part of a media tour to promote his new book, “The Room Where It Happened: A White House Memoir,” which has drawn intense criticism from both Democrats and Republicans since excerpts and advance copies began circulating earlier this month.

The damning 592-page account of Bolton’s 17 months in the White House, decried by Trump as a “compilation of lies and made up stories,” is set to be released Tuesday, despite the Trump administration’s last-ditch attempt to block its publication over allegations that it contains classified information. On Saturday, a federal judge ruled that the book release could proceed but said that Bolton “likely jeopardized national security” and may be at risk of criminal prosecution, The Washington Post’s Spencer S. Hsu and Tom Hamburger reported.

Trump’s fierce pushback to the book didn’t come as a surprise to Bolton.

“It’ll be volcanic, and I’ve expected that from the beginning,” Bolton told Raddatz. “There were times when I was writing this book or getting it ready for publication that I thought, ‘Goodness, this is more trouble than it’s worth.’ But now that we’re at the point, I’m prepared to accept whatever happens.”

In Sunday’s interview, Bolton expanded on revelations in the book, which he argued supports his claims that Trump is “unfit for office” and lacks the “competence to carry out the job.” Describing the president as “erratic and impulsive,” Bolton slammed Trump’s handling of U.S. foreign policy, accusing him of prioritizing reelection and personal relationships over the country’s national security. Bolton highlighted Trump’s dealings with North Korea, Russia, China and Ukraine as prime examples.

Bolton said his book shows “a pattern quite contrary to the image [Trump] would like to convey, of a decisive president who knows something about what he’s doing.” He noted that Trump “very rarely read much” during intelligence briefings and said Trump was unwilling “to do systematic learning so that he could make the most informed decisions.”

“There really isn’t any guiding principle that I was able to discern, other than what’s good for Donald Trump’s reelection,” Bolton said.

He added: “Decisions are made in a very scattershot fashion, especially in the potentially mortal field of national security policy. This is a danger for the republic.”

Bolton painted an unflattering portrait of Trump’s relationships with other leaders, namely Russian President Vladimir Putin — who Bolton said thinks he can play Trump “like a fiddle” — and North Korea’s Kim Jong Un.

He appeared particularly irked by Trump and Kim’s historic 2018 summit, which marked the first meeting between leaders from the United States and North Korea.

“When we were in Singapore for the first summit, one of the things he said over and over again was to ask how many press people were going to be present for his final press conference,” Bolton said. “That’s what he was focused on. That he had had this enormous photo opportunity."

But while Trump succeeded in getting “enormous attention” from the event, Bolton, who has long been a hard-liner on North Korea policy, said he thought it was “a strategic mistake.”

“The U.S. itself got nothing from that. Donald Trump got a lot,” he said. “The United States gave much more legitimacy to this dictator. And didn’t accomplish anything toward any meaningful discussion on the elimination of their nuclear weapons program.”

Instead, Bolton accused Trump of spending a majority of his meetings with Kim flattering the North Korean leader.

“It’s a style. Every president has a style,” Bolton said. “But the idea that … compliments to this brutal dictator would convince him that you could make a deal with Donald Trump, I thought, was both strikingly naive and dangerous.”

In response to Raddatz asking whether the threat from North Korea is greater now than when Trump took office, Bolton said, “The threat from North Korea today is absolutely greater.”

“Because while all these photo opportunities were taking place, there’s absolutely no doubt that North Korea’s work on both its nuclear and ballistic missile programs continued,” he said.

Bolton also defended his decision not to testify in impeachment proceedings against Trump — a move bashed by Democrats in light of the damaging details in his book about Trump’s actions toward Ukraine.

For instance, Bolton recounted a conversation he had with Trump in which the president “directly linked the provision” of sending aid to Ukraine with an investigation into former vice president Joe Biden, who is now the presumptive Democratic nominee. Trump has denied making such comments to Bolton, and during Sunday’s interview, Bolton accused the president of lying.

“It’s not the first time, either,” Bolton told Raddatz. “This is why I think it’s important to get these kinds of facts out on the table.”

But Bolton maintained that his impeachment testimony “would not have made any difference.”

“Minds were made up on Capitol Hill,” he said, referring to impeachment as a “partisan catfight” and denouncing House Democrats’ approach to the proceedings. “My feeling was in the midst of all the chaos that had been created, this would have come and gone, and nobody would have paid any attention to it.”

Bolton suggested that impeachment, which ended with the Senate acquitting Trump, only emboldened the president.

“He didn’t learn lessons from it, other than that he could get away with it, which leaves only the last guardrail — is the election this November,” he said.

Bolton, however, said that while he doesn’t want Trump to win reelection, he is “certainly not going to vote for Joe Biden either.”

“I’m going to figure out a conservative Republican to write in,” he said.

As Bolton tells it, the upcoming election is a large part of why he decided to write the book.

“I want people to read it, not for the conclusions, but for the basic evidence that it provides. They can make up their own minds,” he said. “Some Republicans will read it and say, ‘We’re going to vote for Trump anyway.’ And all I want them to know is what they’re actually voting for.”