Donald Trump has no guiding principles and is unfit to be president, his former national security advisor John Bolton said in an interview released Thursday to promote his explosive book.
"I don't think he's fit for office. I don't think he has the competence to carry out the job," Bolton told ABC News.
The Trump administration is scrambling to stop publication of the memoir, "The Room Where It Happened," arguing that it contains classified material.
In the book, excerpts of which were published by three newspapers Wednesday, Bolton alleged that Trump asked Chinese President Xi Jinping for re-election help, voiced support for Beijing's mass incarceration of Uighur Muslims and other minorities and was widely ignorant of the world.
"There really isn't any guiding principle that I was able to discern other than what's good for Donald Trump's re-election," Bolton told ABC News in the interview, which will be broadcast in full Sunday.
"I think he was so focused on the re-election that longer-term considerations fell by the wayside," he added.
Bolton pointed to Trump's outreach to North Korean leader Kim Jong Un, saying Trump was fixated on the "photo opportunity and press reaction to it" rather than on long-term US interests.
Bolton, a veteran Republican insider, is well-known for his hawkish views on North Korea -- a key reason for his departure from the White House in September.