Mattis isn’t sure he can work with John Bolton

Secretary of Defense Jim Mattis is reportedly not happy about the new appointment of noted foreign policy hawk John Bolton as President Donald Trump's national security advisor.

Mattis "told colleagues before the appointment was announced that he would find it difficult to work with Mr. Bolton," according to the New York Times.

The reason, the Times reports, has to do with Bolton's aggressive rhetoric when it comes to the US's adversaries, especially Iran and North Korea.

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As a general in the Marine Corps, Mattis himself was aggressive towards Iran — so much so that former President Barack Obama replaced him as CENTCOM commander. His selection as Trump's secretary of defense led some to worry that he would bring that attitude to the White House.

But since Mattis' appointment, he has seemingly reversed his course. He argued in support for the continuation of the Iran deal in October 2017, something that Bolton has repeatedly said should be torn up.

The defense secretary joins prominent Democrats, as well as former Bush and Obama administration officials, who have reservations about Bolton's hiring.

With the appointment of Bolton, Mattis looks even more like a moderate — and if the recent shake-ups in the White House are any indication, that may put him on the wrong side of the president.

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Mattis was a close ally of now-fired Secretary of State Rex Tillerson, reportedly having breakfast with him every week. He has notably been reluctant to talk about military actions in North Korea.

"This is a diplomatically led effort," Mattis told reporters asking for details on his plans regarding North Korea in early March 2018. "So I do not want to talk about Korea at all. I'll leave it to those who are leading the effort, the State Department, and the NSC."

White House Chief of Staff John Kelly is also said to be unenthusiastic about Bolton's appointment, reportedly because he is worried that Bolton will "behave like a cabinet official rather than a staff member."