Throughout ISIS's three-month siege of Kobani, the heavily Kurdish Syrian border town, many wondered whether the battle would prove the Islamic State's Waterloo. For a group that so heavily relies on propaganda and momentum, its apparent defeat there this week at the hands of Kurdish forces (backed by American airstrikes) stings far beyond the battlefield.

"ISIL's defeat in Kobane further shatters the organization's claims to invincibility," Al Jazeera's Mohammed Salih writes, "particularly as it coincides with the group's retreat from Kurdish and other Iraqi forces in northern and central Iraq." Some experts have emphasized the importance of the defeat in the context of the group's efforts to mobilize foreign fighters⎯Australians, Canadians, Europeans, and recruits from across the Middle East were among the 1,200 killed in Kobani while fighting under the Islamic State banner.

On Wednesday, a State Department official cautioned against declaring "mission accomplished" in the fight against ISIS, but told Reuters that "the entire notion of this organization that [it] is on the march and the inevitable expansion and inevitable momentum has been halted at Kobani."

This circumspection seems wise considering that as ISIS fighters were being repelled from the last corners of Kobani, the group was announcing itself elsewhere. Earlier this week, fighters in Libya claiming to be affiliated with the Islamic State took credit for an attack on a hotel in Tripoli that killed 10 people, including an American and a French citizen. Over the weekend, news of ISIS's execution of a Japanese hostage drew broad attention as the lives of a second Japanese hostage and a Jordanian pilot, both in ISIS custody, remain in jeopardy.

There's also the matter of what ISIS still controls. As Robin Wright points out, ISIS commands 20,000 square miles of territory across Syria and Iraq, "roughly twice the area of Massachusetts," and hasn't ceded much turf despite thousands of airstrikes by a U.S.-led coalition. “ISIS is still well-entrenched in the areas it controls and still has access to human and other resources,” Dlawer Ala’aldeen, president of the Middle East Research Institute in Erbil, told Time. “It’s not the beginning of the end," he said.

With the attention of Kurdish forces turning toward Mosul, Iraq's second-largest city, which was overrun by Islamic State forces last June, that may all change, but not without a lot of help. Will Mosul be ISIS's Waterloo? Sure. Until the next one, of course.

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