12/20/2018 05:02 PM EST
Vehicles of the US-led coalition battling the Islamic State group patrol the town of Rmelane in Syria’s Hasakeh province on June 5. | Delil Souleiman/AFP/Getty Images
President Donald Trump’s abrupt announcement that “we have defeated ISIS” in Syria and U.S troops are “all coming back and they’re coming back now” raises a series of unanswered questions.
How will the pullout be implemented and over what time frame? What’s the role of Congress? How will it impact the regional cauldron stirred up by Syria’s seven-year civil war?
Here’s a primer on Trump’s decision, which has drawn bipartisan criticism and was reportedly opposed by many of Trump’s own national security team.
Who’s fighting in Syria now?
A long list of key players have been combatants, broadly divided between internal and external forces.
Roughly 2,000 U.S. special operations troops, backed by Air Force and Navy combat planes, are working “by, with and through” allies on the ground who have steadily recaptured territory from ISIS, which withdrew from the last town they controlled in Syria last week.
The Pentagon stated in an inspector general report back in June that ISIS has nearly 30,000 fighters across Iraq and Syria.
U.S. partners have included the Syrian Democratic Forces, an alliance of Arab, Kurdish and other militias, as well as the YPG, the main Kurdish militia in Syria that is considered a terrorist group by Turkey, America’s erstwhile ally.
In addition to ISIS, those groups have faced off against the regime of Syrian President Bashar Assad, who is accused of war crimes against the civilians, including with poison gas.
After years of combat, however, Assad’s forces are a “hollow shell” of their former strength and “don’t have striking power,” says David Adesnik, director of research at the Foundation for Defense of Democracies, a hawkish think tank.
But the war has also become a flash point for Great Power competition: Russia says it still maintains more than 60,000 troops in the country to prop up Assad’s government and battle Sunni Arab groups opposed to the regime.
Additionally, Iran and its proxy forces, including the terrorist group Hezbollah, have committed significant blood and treasure to supporting Assad. Reports have suggested Iran spends approximately $16 billion annually.
Finally, Turkey, whose primary objective remains to crush Kurdish opposition along its border, has launched two major incursions into Northern Syria in recent year to fight against both ISIS and Syrian Kurds.
When will U.S. troops leave?
Defense Department officials have said the president has ordered the U.S. withdrawal to be complete within 30 days.
But significantly, the president has not publicly set a calendar date for withdrawal, noted Anthony Cordesman, a strategist at the Center for Strategic and International Studies.
That could provide some flexibility as senior Defense Department officials and military leaders determine how best to implement the president’s order.
How quickly a withdrawal proceeds also depends on how much time the U.S. wants to give its partners to prepare for operations without U.S. support — including American air power — according to specialists in the conflict.
“If the goal is to do this like Dunkirk, we could do it this year,” Adesnik said, referring to the abrupt withdrawal of British troops from Western France in 1940.
What about airstrikes?
The withdrawal of U.S. ground forces from Syria reportedly also means an end air strikes in the country as well, according to senior defense officials. Ground troops help ensure accurate targeting of ISIS forces and the avoidance of civilian casualties, Cordesman explained.
But the air war has shown little sign of dying down even with the victories over ISIS: The U.S.-led coalition tasked with defeating ISIS in the region last week carried out 208 airstrikes in Syria, according to data released Wednesday. The Combined Joint Task Force – Operation Inherent Resolve, the headquarters in charge of the campaign, noted the U.S. and its allies “continue to pursue the lasting defeat of ISIS in designated parts of Iraq and Syria.”
Britain and France, which both conduct air strikes in Syria as poart of the coalition, both stated their commitment on Thursday to continue the campaign.
What can Mattis do?
Not much to stop the withdrawal, unless he changes the president’s mind.
Senior Trump aides have been mostly publicly quiet since the announcement. But in recent weeks they have stressed the importance of keeping some U.S. troops in Syria to combat Iran’s influence.
Brett McGurk, the State Department’s special envoy for the global effort to defeat the Islamic State, said last week “it would be reckless if we were just to say, ‘well, the physical caliphate is defeated, so we can just leave now.’ I think anyone who’s looked at a conflict like this would agree with that.”
Defense Secretary Jim Mattis, who has been a vocal supporter of maintaining a military presence not just to fight ISIS but counter Iranian influence, could resign if he decides he will not implement the Trump’s order, said Adesnik.
But “this is a rightful decision for the commander-in-chief to make,” said Jennifer Cafarella, the director of intelligence planning at the Institute for the Study of War, a Washington think tank.
What can Congress do?
There’s likely not much Congress can do to bar Trump from pulling out troops. But lawmakers could use their considerable oversight power to demonstrate the strategic risks of leaving Syria too early. And in so doing, they could possibly pressure the White House to change course.
The withdrawal has drawn scorn from both sides of the aisle on Capitol Hill, including some of Trump’s staunchest backers in his own party.
In a letter to Trump on Wednesday, Sens. Joni Ernst (R-Iowa), Lindsey Graham (R-S.C.), Tom Cotton (R-Ark.), Marco Rubio (R-Fla.), Jeanne Shaheen (D-N.H.) and Angus King (I-Maine) warned the commander-in-chief to “not repeat the same mistakes that previous administrations have made,” in reference to the U.S. withdrawal from Iraq at the end of 2011, leaving what many view as a vacuum for ISIS.
“We believe that such action at this time is a premature and costly mistake that not only threatens the safety and security of the United States, but also emboldens ISIS, Bashar al Assad, Iran, and Russia,” the senators wrote.
What about the Kurds?
Apart of the hundreds of thousands of civilians believed to have been killed, Syrian Kurds are likely to suffer most from a U.S. withdrawal.
An array of forces — including Turkey, Assad, ISIS and possibly others — could turn their guns on the U.S.-ally.
On Thursday, Turkey’s defense minister said Syrian Kurdish militants allied with Washington “will be buried in their ditches when the time comes.”
“The Kurds are about to be abandoned in one of the most despicable fashions the United States has abandoned an ally in this generation,” said Michael O’Hanlon, a military and foreign policy specialist with the Brookings Institution.
Much remains unknown, but one possible outcome for the Kurds is that they cut a deal with Assad, exchanging territory they have captured in the war for a ceasefire or protection, Cafarella said.
Even so, the Kurds “face a series of very bleak options,” she added.