Former Secretary of State Rex Tillerson’s ouster from the State Department means the man who allegedly called the president a "moron" is gone.

But what does his removal mean for foreign policy? National security expert Juliette Kayyem joined Boston Public Radio to explain what his exit represents.

Tillerson was one of the last moderates working under the Trump White House, said Kayyem, who added that he was part of the last stand “that relied on allies, viewed China as a rising concern and Russia as a very strategic menace.”

“His departure will mean one of those key people is gone,” said Kayyem.

She also pointed out that Trump’s reasoning for firing Tillerson was that they diverged on the Iran deal. Kayyem said almost all of the United State’s military leaders are in favor of the deal, and Trump’s opposition to it is a foreign policy mistake.

“To abandon it would essentially say to North Korea and any other country, ‘Any deal in which you’re willing to not expand your nuclear arsenal, and even if you abide by it, we may walk away from,’” she said. “That’s not a very good bargaining position for the United States.”

Juliette Kayyem is a national security expert, a member of the faculty of Harvard’s Kennedy School and the CEO of ZEMCAR.