Wednesday's attack on U.S. forces in Syria has stoked fresh criticism over President Donald Trump's claim that the so-called Islamic State has been defeated renewed debate over his decision to withdraw all troops from the war-torn country.
Around 1 p.m. local time, a suicide bomber blew himself up in a popular area of downtown Manbij, a northern Syrian city that's been controlled by U.S.-supported Kurdish militias since it was wrested from ISIS in 2016.
Four Americans were killed — two service members, a civilian Pentagon official and a U.S. contractor — and three more injured, U.S. Central Command confirmed in a statement, reportedly marking the largest single loss of American life since the counter-ISIS campaign began. Nineteen people are believed to have died in total, including civilians and local coalition partners, according to monitoring group the Syrian Observatory for Human Rights.
ISIS quickly claimed responsibility. While the group has not so far offered physical evidence to support the claim, critics have been quick to link the attack to President Donald Trump's decision last month to withdraw all U.S. troops from Syria.
"Trump's order was reckless and driven far more by domestic political concerns than it was by facts on the ground," Charles Lister, a senior fellow at the Middle East Institute, said on Twitter Wednesday.
Trump defended the troop pullout plans on the premise that ISIS had been defeated. The decision triggered rebukes from numerous lawmakers and security experts, who warned of the extremist group's resurgence and lamented what was seen as an abandonment of local partners.
"Sometimes reality catches up quickly with wishful thinking and political spin," Michael Rubin, a former Pentagon official and resident scholar at the American Enterprise Institute in Washington, D.C., told CNBC on Wednesday. "Historians will likely file Trump's tweets announcing the ISIS defeat and U.S. Syria pullout alongside Bush's 2003 'Mission Accomplished' speech and Obama's 2011 withdrawal from Iraq."
The counter-ISIS campaign, started under the Obama administration and continued under Trump, has decimated the group's territorial hold and its numbers compared to what it controlled at its height. In January 2015, ISIS held an estimated 50,000-plus square miles in Syria and Iraq and fielded close to 100,000 fighters, according to some estimates. In December, top U.S. officials told CNBC the group only controlled 1 percent of what they once had.
But the Manbij attack, and continued low-level kidnappings and attacks elsewhere in Syria and Iraq, are a reminder that its sleeper cells exist and its ideology has yet to be defeated.
"The attack in Manbij demonstrates clearly that ISIS still has an extensive network of operatives throughout the areas it used to control in Syria, and that it wants the world to know that," said Nick Heras, a Middle East security fellow at the Center for a New American Security and former research associate at the National Defense University. "ISIS likely timed the attack to send the message to Trump that he hasn't beat it yet, and to the world that the Americans will lose the long war against it."
However, it's important to note that this type of attack, carried out against U.S. personnel in a civilian area, "is a low hanging fruit operation" that ISIS could execute with or without Trump's announcement of the Syria drawdown, Heras added. The group's predecessors in Iraq carried out similar attacks frequently, and we should expect more of them in Syria moving forward, he said.
"ISIS has an incentive to demonstrate to everyone that it is not dead, that it has agents and capabilities everywhere, and that its return in Syria is inevitable."
The White House has not commented on how the attack may impact U.S. plans to withdraw troops from the country, though the process has already begun, according to the Pentagon. White House Press Secretary Sarah Sanders expressed condolences to the families of those lost in a statement Wednesday.
Just hours before the attack, Vice President Mike Pence told a group of U.S. ambassadors gathered in Washington that "The caliphate has crumbled, and ISIS has been defeated."
While Wednesday's attack appears to prove that assertion wrong, terrorism analysts point out that "defeat" of a jihadist group may no longer even be relevant as a term if used in the sense of conventional warfare. ISIS, like many of its counterparts, can survive as an ideology without commanding a physical territory or army, they say, meaning that regardless of a territorial defeat, individuals and cells acting independently can theoretically carry out the group's mission forever.
Council on Foreign Relations President Richard Haass drove this point home.
"The apparent ISIS attack in Syria a costly reminder that there is no such thing as victory in any traditional sense vs terrorists," he said on Twitter. "This is one reason why 'war' is not a good term in this context as classic wars have an end but struggles vs terrorists are unavoidably open ended."