Mattis to step down, acknowledges he and Trump aren't aligned on key issues

Defense Secretary Jim Mattis will step down from his position at the end of February, telling President Trump in a resignation letter sent today that he should have a Pentagon chief whose views "are better aligned" with his.

In the Dec. 20 letter to the president, Mattis writes, "our strength as a nation is inextricably linked to the strength of our unique and comprehensive system of alliances and partnerships." The United States must confront Russia and China, he continued, whose views "are increasingly in tension with ours."

In an unmistakable rebuke to Trump, Mattis writes his "views on treating allies with respect and also being clear-eyed about both malign actors and strategic competitors are strongly held and informed by over four decades of immersion in these issues. We must do everything possible to advance an international order that is most conducive to our security, prosperity and values, and we are strengthened in this effort by the solidarity of our alliances.”

"Because you have the right to have a Secretary of Defense whose views are better aligned with yours on these and other subjects, I believe it is right for me to step down from my position," Mattis continues.

His last day will be Feb. 28, the letter continues, to allow time for a successor to be nominated and confirmed. Mattis wrote the time frame would also allow him to represent Defense Department's interests at congressional posture hearings, as well as at the NATO defense ministerial meeting in February.

His resignation comes just a day after Trump surprised Washington and the world by deciding to begin pulling U.S. troops out of Syria, a move that has sparked bipartisan concern on Capitol Hill.

"We are concerned that it would be a strategic error to remove U.S. forces precipitously from Syria without regard to the impact it might have on our ability to consolidate our military gains against ISIS, ensure the safety of our partners, including the Kurds and other Syrian Democratic Forces, and uphold regional stability against malign actors such as Russia and Iran. ISIS was and still remains a lethal threat to America's security and will seek to inspire threats to the homeland from safe havens around the world," reads a joint statement -- issued before the news of Mattis' retirement -- from House Armed Services Committee Chairman Mac Thornberry (R-TX) and Rep. Adam Smith (D-WA), the committee’s ranking member.

Just before DOD released Mattis' resignation letter, Trump announced the news on Twitter.

"General Jim Mattis will be retiring, with distinction, at the end of February, after having served my Administration as Secretary of Defense for the past two years," Trump wrote in a pair of tweets tonight. "During Jim's tenure, tremendous progress has been made, especially with respect to the purchase of new fighting equipment.

"General Mattis was a great help to me in getting allies and other countries to pay their share of military obligations," Trump continued. "A new Secretary of Defense will be named shortly. I greatly thank Jim for his service!"

Following the announcement, Senate Armed Services Committee Chairman Jim Inhofe (R-OK) in a statement said Mattis "led us through rebuilding our military after the readiness crisis to developing a forward-thinking National Defense Strategy that prepares our military for the realities of the future. It is a shock to everyone that a career Marine with the nickname of 'Mad Dog' was genuine, gentle and understanding. He was devoted to the warfighter, military families and veterans. I always valued our close working relationship and our nation is better for his lifetime of service."