With Russian flags now flying over abandoned U.S. military bases in Syria, and American soldiers still dying in combat with the Islamic State in Iraq, the terror group’s strength may seem hard to gauge. Yet the Russian and American presidents have each suggested at different times that ISIS, as the group is also known, has been eliminated and that it was their respective militaries that had contributed the most to achieve that result. President Donald Trump, for example, effectively announced the group’s defeat by U.S. troops on July 16, 2019: “We did a great job with the [ISIS] caliphate. We have 100 percent of the caliphate and we’re rapidly pulling out of Syria,” he said at a Cabinet meeting. President Vladimir Putin has made similar comments about the role of Russia and its soldiers. In early December 2017, a few days after the Defense Ministry officially told him that “all ISIS gangs on Syrian territory have been destroyed and the territory itself has been liberated,” Putin travelled to Syria and addressed Russian troops at the Hmeimim military base, saying that, “in a little more than two years, Russia’s Armed Forces, together with Syria’s army, routed the most battleworthy group of international terrorists [there was].”

These claims of victory raise at least two important questions: First, to what extent has ISIS been defeated and, second, which country, the United States or Russia, deserves credit for contributing the most to this cause? The short answer would be this: The U.S.-led coalition did far more to clear ISIS out of Iraq and Syria than Russia and its allies; however, even though the terror group no longer controls significant territory in these countries, its fighters continue to carry out deadly attacks there, waging what the Institute for the Study of War recently called “a capable insurgency” with “a global finance network,” showing that any purported victory over ISIS—whether claimed by Washington or Moscow—is extremely “fragile.”¹