Though initially popular with President Donald Trump, Defense Secretary Jim Mattis saw his influence wane in recent months. | Drew Angerer/Getty Images Defense Mattis breaks with Trump in resignation letter “You have the right to have a secretary of defense whose views are better aligned,” the defense secretary told him Thursday.

Defense Secretary Jim Mattis resigned on Thursday while delivering a stunning rebuke to President Donald Trump, expressing differences on issues including the president's treatment of U.S. allies and the need for a "resolute" approach to Russia.

"Because you have the right to have a secretary of defense whose views are better aligned on these and other subjects, I believe it is right for me to step down from my position," Mattis told Trump in his resignation letter.



The highly public end to Mattis' two years as Pentagon leader came a day after Trump announced an abrupt pullout of U.S. forces from Syria, a move that shocked allies in the region and knocked military commanders off guard. It also followed reports that Trump is poised to order a similarly swift withdrawal from Afghanistan.


And his departure unnerved lawmakers who had looked to the retired four-star Marine general as a rare force for stability in Trump's administration — someone who had repeatedly counseled the president against taking precipitous actions in hot spots like Syria, Iran, and the Korean peninsula.

"I’m shaken by the news because of the patriot that Secretary Mattis is," said House Democratic leader Nancy Pelosi. "I think that everybody in the country should read his letter of resignation. It’s a letter of great patriotism, but respect for the president, but also a statement of his values."

"This is scary," tweeted Sen. Mark Warner, a Democrat from Virginia. He added: "As we’ve seen with the President’s haphazard approach to Syria, our national defense is too important to be subjected to the President’s erratic whims."

Senate Majority Leader Mitch McConnell lauded Mattis's staunch support for "post-World War alliances that have been carefully built by both parties."

"We must also maintain a clear-eyed understanding of our friends and foes, and recognize that nations like Russia are among the latter," he said in a statement, adding he is "particularly distressed that he is resigning due to sharp differences with the president on these and other key aspects of America’s global leadership."

“It is regrettable that the president must now choose a new Secretary of Defense," McConnell continued. "But I urge him to select a leader who shares Secretary Mattis’s understanding of these vital principles and his total commitment to America’s servicemembers.”

Another Republican, Illinois Rep. Adam Kinzinger, tweeted in response to Trump's announcement: "That’s what happens when you ignore sound military advice."

Trump tried to paint a more flattering picture of Mattis' departure, announcing — via Twitter, of course — that the Pentagon chief is "retiring" in February.

"General Mattis was a great help to me in getting allies and other countries to pay their share of military obligations," Trump wrote. "A new Secretary of Defense will be named shortly."

The Pentagon released the resignation letter minutes later.

The letter was a departure for Mattis, who had always been careful not to criticize the president publicly. But it had been clear for some time that Mattis, once a darling of Trump's Cabinet, had become a dissident on a host of issues, including the president's desire for a Space Force, the proposed ban on transgender troops and the deployment of thousands of troops to the U.S.-Mexican border.

But Trump's Syria pullout, combined with fears of Trump will also overrule his advisers on Afghanistan, were just too much, a former Pentagon official told POLITICO, “Those are the last straws."

The move also comes as Trump realigns his Cabinet and senior White House staff in the wake of hefty Republican losses in the Nov. 6 midterm elections. Attorney General Jeff Sessions was the first departure, ousted on the day after the elections, and the fall of scandal-tarred Interior Secretary Ryan Zinke — a retired Navy SEAL — came just last weekend.

Though initially popular with Trump, Mattis — whom the president enjoyed calling by his nickname "Mad Dog" — saw his influence wane as Trump turned more toward hawks in his inner circle like Secretary of State Mike Pompeo and White House national security adviser John Bolton.

In his letter Thursday, Mattis made clear that the two had steadily parted company. On China and Russia, he told Trump: "I believe we must be resolute and unambiguous in our approach to those countries whose strategic interests are are increasingly in tension with ours."

He also alluded to Trump's shabby treatment in public of longtime American allies.

"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 allies."

Mattis proved to be popular on Capitol Hill in his nearly two years on the job and was one of the few administration officials with the trust of lawmakers from both parties. In the months leading up to his departure, Democrats and Republicans alike praised Mattis' performance and urged him to stay on the job.

"Secretary 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," Senate Armed Services Chairman Jim Inhofe (R-Okla.) said in a statement Thursday.

He also praised Mattis as a person. "It is a shock to everyone that a career Marine with the nickname of ‘Mad Dog’ was genuine, gentle and understanding," Inhofe wrote.

Trump critics have long seen Mattis, a retired four-star Marine general and a professed nonpartisan, as a moderating force and steady hand within a chaotic administration. His overwhelming Senate confirmation included support from even senators who have since opposed nearly all of Trump's nominees.

As the Pentagon's top civilian, Mattis pushed for largely a continuation of strategies the military was already pursuing in its campaign against ISIS in Iraq and Syria and the war in Afghanistan. He opposed withdrawing from the nuclear pact with Iran.

Just who will step in to replace Mattis is unclear, though some speculation has centered on retired Army Gen. Jack Keane and Republican Sen. Tom Cotton of Arkansas.

A Democratic-controlled House is likely to be more demanding of both military and civilian Pentagon leaders and take a more skeptical eye toward historically high defense budgets and key policies, such as overhauling each leg of the U.S. nuclear arsenal and continuing military assistance for the Saudi-led intervention in Yemen's civil war.