Former Secretary of Defense James Mattis has maintained a professional demeanor regarding his decision to resign last December.

Mattis, however, said his silence and respect toward President Donald Trump will not last forever.

The retired Marine Corps four-star general resigned from his Secretary of Defense position last December. The decision arose over policy differences – specifically, the opposing opinions over whether or not to pull American troops out of Syria.

Mattis said he had no choice but to resign. He pleaded with Trump to keep U.S. troops in Syria. When Trump decided to withdraw them, Mattis told him, “You’re going to have to get the next Secretary of Defense to lose to ISIS.”

The former Secretary of Defense stated in an interview, “I owe my silence.” However, he also noted, “[my silence] is not eternal, it is not going to be forever.” Mattis defended his decision in his book, which also includes his letter of resignation.

The former Marine Corp said, “I’ve been informed by four decades of experience. And I just couldn’t connect the dots anymore.”

Upon being nominated for the Secretary of Defense position, Mattis stated decades of military service made him feel prepared and confident in his ability to make sound decisions. He, however, was initially surprised when Trump asked to meet with him in 2016 in Bedminster, New Jersey, to discuss the job. He voiced concern over their opposing political opinions and strategies. After the meeting, Mattis wrote, “I figured that my strong support of NATO and my dismissal of the use of torture on prisoners would have the president-elect looking for another candidate.”

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