WASHINGTON _ President Donald Trump's national security team continued to disintegrate over the weekend, as the administration's senior envoy to the global coalition fighting Islamic State quit over the president's abrupt decision to withdraw U.S. forces from Syria.
The resignation of Brett McGurk, one of the most important U.S. diplomats in the Middle East, follows that of Defense Secretary James F. Mattis, who announced his resignation Thursday, citing concerns about Trump's increasingly isolationist foreign policy.
McGurk's departure leaves the U.S. with another leadership hole, as he was a seasoned and well-regarded veteran with experience on the ground in the Middle East and in Washington.
McGurk was the principal envoy to the Syrian insurgency that Washington has backed for most of the decade, and a leading strategist in the international fight against Islamic State militants.
In leaving, McGurk warned against Islamic State's sustained ability to mount attacks, offering a direct challenge to the president's assertions that the group has been defeated.
McGurk submitted a letter of resignation to Secretary of State Mike Pompeo on Friday night, a State Department official said, speaking anonymously because of the government shutdown. The resignation is effective Dec. 31, the official said.
McGurk's resignation comes at a time when Trump is increasingly isolated, with the last of the most talented members of his administration leaving even as it becomes increasingly difficult for the president to hire qualified replacements.
Trump still has not found a permanent replacement for White House Chief of Staff John F. Kelly, whose resignation was announced earlier this month. And the president's pick to replace Attorney General Jeff Sessions appears likely to face a contentious path to confirmation in the Senate amid revelations that he has sharply criticized the investigation of special counsel Robert S. Mueller III.
McGurk, 45, previously clerked for the late Chief Justice William H. Rehnquist and was a senior State Department official dealing with Iraq and Iran in President George W. Bush's administration.
He worked on nuclear negotiations with Tehran, and was appointed a special envoy in 2015 by President Barack Obama. Trump kept him on after taking office in 2017.
Like most of Trump's national security advisers, Pentagon officials and U.S. diplomats, McGurk disagreed openly with the president's recent claim that Islamic State was defeated. Despite huge losses of territory in Syria and Iraq, Islamic State remains a threat that can potentially regroup and re-emerge, McGurk and others assert.
"It would be reckless if we were just to say, 'Well, the physical caliphate is defeated, so we can just leave now,'" McGurk said at a State Department briefing on Dec. 11. "Anyone who's looked at a conflict like this would agree with that."
Even as the group's self-described caliphate disappears, McGurk added, "the end of (Islamic State) will be a much more long-term initiative.
"Nobody is declaring a mission accomplished."
Eight days later, Trump made the surprise announcement that he was withdrawing an estimated 2,000 U.S. troops and other personnel from Syria, declaring Islamic State was no longer a threat.
"We have defeated ISIS in Syria, my only reason for being there during the Trump Presidency," Trump tweeted Wednesday.
On Saturday, despite Mattis' resignation and almost universal bipartisan condemnation of his Syria move, Trump continued to defend his decision.
"On Syria, we were originally going to be there for three months, and that was seven years ago _ we never left," he tweeted. "Now (Islamic State) is largely defeated and other local countries, including Turkey, should be able to easily take care of whatever remains. We're coming home!"
The announcement fulfilled a campaign promise that Trump repeatedly made while running for president.
However, many Middle East experts say Trump's decision, in addition to clearing the way for Islamic State to return, handed victories to U.S. adversaries, including Iran, Russia and Syrian President Bashar al-Assad. All three have made steady military gains in the waning years of the Syrian civil war.
The U.S. withdrawal also rewards NATO ally Turkey, whose authoritarian government bitterly opposes U.S. support for Kurdish fighters in Syria. These fighters have been Washington's strongest partners in fighting Islamic State as well as Assad's forces, but are viewed by Turkey as a threat.
Turkey had long viewed McGurk as the lead U.S. champion of those Kurdish fighters, known as the Syrian Democratic Forces, and his departure is likely to be seen by Turkey as another victory.
McGurk was instrumental in corralling a fractious coalition against Islamic State, bringing together groups with often competing agendas, including those supported by Iran, to oust the jihadist militants from their de facto capitals of Mosul, Iraq, and Raqqa, Syria.
Although some of McGurk's legacy in the region will undoubtedly be challenged, foreign policy experts and former officials agreed on McGurk's important role in events in the region in recent years.
"Brett McGurk has served Presidents Bush 43, Obama and Trump with extraordinary dedication and persistence," Nicholas Burns, a former assistant secretary of State, said on Twitter. "A real loss for the (U.S. government). But who can blame him."
John Brennan, a former CIA director and frequent critic of Trump, said McGurk ensured the United States was fulfilling its leadership role in a troubled part of the world.
"Like Sec. Mattis, Brett believes in the principles, values, & partnerships that define America," Brennan said on Twitter. "Donald Trump does not."
McGurk's warnings earlier this month against abandoning the fight against Islamic State were echoed by senior Pentagon officials.
Gen. Joseph Dunford, chairman of the Joint Chiefs of Staff, said early this month that the U.S. had not yet adequately trained Syrian forces to prevent a resurgence of Islamic State. He said it would take 35,000 to 40,000 local troops in northeastern Syria to maintain security over the long term, but only about 20 percent of that number had been trained.
