With Mattis Gone, Is Trump Unleashed?

The resignation of U.S. Defense Secretary James Mattis on Thursday over President Donald Trump’s abrupt decision to withdraw all U.S. troops from Syria marks the departure of one of the last members of the president’s cabinet willing to stand up to their boss, leaving the U.S. national security community and allies abroad fearing the worst.

The revered retired U.S. Marine Corps general, who is commonly referred to as the “last adult in the room,” has been seen as the voice of reason in an otherwise chaotic administration. During the first months of his term, Mattis was seen as one of the most influential voices in Trump’s orbit, a rare cabinet member with the power to curb the president’s worst impulses. Early on, he notched a string of successes, securing a significant budget increase for the Defense Department and a troop increase for Afghanistan. He also reportedly resisted Trump’s impulses to call a strike on North Korea and assassinate Syrian President Bashar al Assad.

Most significantly, Mattis has served as a reassuring presence to U.S. allies, from Europe to the Middle East, and reportedly prevented Trump from taking the most extreme actions. In his resignation letter, the defense secretary appeared to take Trump to task over the president’s treatment of those countries, saying, “Our strength as a nation is inextricably linked to the strength of our unique and comprehensive system of alliances and partnerships.”

Reports emerged Saturday that Brett McGurk, the special presidential envoy for the global coalition to counter the Islamic State, has followed Mattis’ lead and submitted his own resignation due to the president’s decision.

Experts said Mattis’s departure could mean more impulsive decisions that alienate US allies—for instance, withdrawing U.S. troops from South Korea or unilaterally pulling out of NATO.

“I think pretty much anyone who exists on social media apparently thinks that Mattis was the only thing keeping Trump from doing everything that Trump promised he would do,” said Loren DeJonge Schulman, the deputy director of studies at the Center for a New American Security. “I would anticipate that we will see more, if not serious actions like withdrawal from alliances, but more obnoxious posturing from the administration.”

Members of Congress also decried Mattis’s departure, and some experts such as DeJonge Schulman are hoping Capitol Hill will step up to check Trump in Mattis’s place. Democratic Sen. Bob Menendez, the ranking member of the Senate Foreign Relations Committee, expressed concern about Trump’s “dangerous and erratic decision-making.”

“As this Administration continues to implode, Secretary Mattis’ extraordinary resignation is a significant loss and a real indication that President Trump’s foreign policy agenda has failed and continues to spiral into chaos,” Menendez said. “As Secretary Mattis makes clear in his letter, President Trump’s coziness with authoritarian regimes and his animosity to our closest allies are increasingly indefensible.”

But despite his initial influence, Mattis has been losing battles with the president for months. Trump has consistently dismissed Mattis’s advice on critical decisions, leaving the defense secretary to do damage control with alarmed U.S. allies.

Although the decision to withdraw from Syria at a crucial moment, leaving the U.S.-backed Syrian Kurds at the mercy of Turkish President Recep Tayyip Erdogan, was the final straw, Mattis had been considering resigning for months, sources told Foreign Policy.

Mattis first drafted a letter of resignation after Trump canceled military exercises with South Korea last summer, according to one source with knowledge of the discussions. The defense secretary was also miffed that the president, against his advice, ordered the creation of a separate Space Force. Most recently, Trump tapped Army Chief of Staff Mark Milley to replace Gen. Joseph Dunford as chairman of the Joint Chiefs of Staff, months ahead of schedule and despite Mattis’s stated preference for Air Force Chief of Staff David Goldfein.

Trump’s decision to withdraw from the Iran nuclear deal is another glaring example of the differences between the two men.

The president himself signaled that the relationship was souring in an October 60 Minutes interview, just weeks after an explosive new book by journalist Bob Woodward alleged that Mattis was quietly trying to undercut many of Trump’s orders. Trump slammed Mattis as “sort of a Democrat” and hinted he may leave the administration.

In the end, Mattis resigned voluntarily, a senior U.S. defense official told FP.

“It wasn’t a forced resignation,” the official said.

Dana White, the Pentagon’s chief spokesperson, said Mattis briefed his senior staff after his return from the White House around 5 p.m. on Thursday night.

“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 wrote to Trump in his resignation letter.

Mattis’s last day at the Pentagon will be Feb. 28.

The question now is: Who will Trump tap to replace Mattis? According to one U.S. administration official, Deputy Defense Secretary Patrick Shanahan is a “serious” contender.

“He and the president get along, and Shanahan has no ideological baggage,” said another source with knowledge of the White House shortlist.

Lt. Col. Joseph Buccino, a spokesman for Shanahan, declined to comment on whether the deputy secretary is in the running.

“Deputy Secretary Shanahan remains solely focused on implementing the National Defense Strategy,” Buccino said.

Another top contender is David McCormick, a West Point graduate, combat veteran, and co-CEO of the global macro investment firm Bridgewater Associates, the two sources told FP. McCormick runs in the same social circles as Trump’s daughter Ivanka Trump and her husband, Jared Kushner, and he is the fiancé of Dina Powell, Trump’s former deputy national security advisor for strategy.

Dan Coats, Trump’s director of national intelligence; Tom Cotton, the 41-year-old Arkansas Republican who chairs the Senate Armed Services Committee’s subcommittee on airland; and Navy Secretary Richard V. Spencer are also on the shortlist, according to the second source.

This report has been updated to reflect reports Saturday of Brett McGurk’s resignation.