In another long-anticipated, and yet still surprising move, U.S. President Donald Trump has fired National Security Adviser H.R. McMaster and announced that he will be replaced by John Bolton, a former ambassador and hard-line analyst. The move reflects the president's growing level of comfort in the job, and the belief that he no longer needs advisers who challenge his views. The Bolton appointment is one more step toward an unfettered Trump presidency, and one that rightfully worries many outside the administration.

McMaster was an awkward fit in the Trump White House. He replaced Michael Flynn, one of Trump's most trusted national security advisers, after he was forced to step down for lying to investigators about contacts with Russia during the presidential transition. There have long been reports of Trump's displeasure with McMaster, a three-star general, who is best known for his thesis — subsequently turned into a book — that the U.S. military was derelict in its duty by not challenging the civilian leadership during the Vietnam War. The president was unhappy with McMaster's style and personality: The national security adviser was said to be prone to lectures, gruff and condescending, and did not give Trump options that the president wanted.

Rumors of McMaster's departure had been floated for months and consistently denied by the White House. All the while, however, conversations were taking place about his replacement. The last straw for Trump was reportedly the leak that he had ignored advice to not congratulate Russian President Vladimir Putin in a phone call after his re-election last week.