June 18 (UPI) -- Former national security adviser John Bolton, who is highly critical of President Donald Trump in an upcoming book, said in an interview broadcast Thursday his former boss and commander in chief is incompetent and unfit for office.
Bolton told ABC News that Trump, for whom he served as national security adviser for 17 months, is primarily motivated in his actions as president by winning a second term.
"There really isn't any guiding principle that I was able to discern other than what's good for Donald Trump's re-election," he said in the interview.
"He was so focused on the re-election that longer-term considerations fell by the wayside."
The Bolton interview is part of an ABC News program scheduled for broadcast Sunday.
Bolton's book, The Room Where It Happened, is set for release on Tuesday. In it, Bolton makes several accusations against the president, including that he's "stunningly uninformed," does not know basic facts and is easily manipulated by foreign leaders.
Bolton also said in the interview that Trump's interactions with foreign policy caused him great concern, particularly a historic summit with North Korean leader Kim Jong Un in 2018.
"I was sick at heart over Trump's zeal to meet with Kim," he said. "There was considerable emphasis on the photo opportunity and the press reaction to it and little or no focus on what such meetings did for the bargaining position of the United States."
Trump has called Bolton "a liar" and said he fired him as national security adviser. Bolton, who clashed with Trump and other advisers before leaving the White House last September, counters that he resigned.
Trade adviser Peter Navarro told reporters at the White House Thursday the driving force behind Bolton's book is money and likened the forthcoming memoir to "Washington revenge porn."
"He got fired because he did not obey the chain of command, because his views were totally out of sync with President Donald J. Trump with respect to how to handle international affairs," Navarro said. "He's basically breaking all manner of tradition in terms of issuing a book at this stage, and he will make a bunch of money."
Navarro dismissed two key accusations in the book -- that Trump asked Chinese President Xi Jinping to buy U.S. agriculture products to enhance his 2020 election prospects and that he endorsed internment camps built to imprison members of China's Uighur minority.
The broadcast of Bolton's interview Thursday came after the Justice Department escalated a legal challenge to block his book. The department appealed to a judge late Wednesday, saying the memoir contains potentially harmful classified information, and asked for a hearing Friday.