REUTERS/Stringer
An Islamic State militant announces to residents of Taqba city that Tabqa air base has fallen to Islamic State militants, in nearby Raqqa city August 24, 2014.
"The [administration's] two-pronged approach makes sense: contain ISIS's gains with limited intervention while seeing how much of a coalition the U.S. can build for broader engagement and how much progress can be made with the Iraqi government and the Syrian rebels," Bremmer, president of the Eurasia group, told Business Insider in an email.
The U.S. is currently building a large coalition of allies and partners in the region to invest in a years-long campaign to bomb ISIS targets from the air in Iraq, equip and train the Iraqi military and Kurdish forces, and confront the extremist group in Syria.
The immediate issue is that the U.S. has a lack of effective partners on the ground, given that most moderate Sunnis have either condoned ISIS rule or succumbed under sheer force. And Obama has drawn a line at committing U.S. ground troops to either Iraq or Syria.
The self-declared Islamic State has "arisen, and gained power, in the heart of the Sunni Arab world," Middle East analyst Hussein Ibish explained recently. "Accordingly, they cannot but be recognized as reflecting a profound crisis in the culture and hierarchies of moral and religious values that have taken root in parts of those societies."
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Western-backed Syrian rebels may turn out to be viable U.S. partners, but they are poorly equipped and currently fighting for their lives in Syria's largest city of Aleppo. Sunni tribes in Iraq, who helped American troops fight ISIS-predecessor AQI (al-Qaida in Iraq) during the Iraq war, have now allied with ISIS to fight the Shia-dominated central government.
"The ranks of moderate Sunnis were not influential or large enough to base an anti-Assad strategy on back when the U.S. was debating its Syrian civil war strategy," Bremmer said. "The same holds true with regards to ISIS today, even when the moderate Sunnis in Iraq and Syria are taken in tandem. Although they are a relevant piece of any strategy, they cannot stand in for the support of a broad coalition of allies as the U.S. debates how to ramp up its ISIS response."
Bremmer expects countries to pitch in to the anti-ISIS campaign in various ways, but noted that "building up workable institutions to replace ISIS rule is much more difficult. It's not something I'm optimistic about."
For example, ISIS administers a de facto capital in Raqqa, Syria, and is attempting to shape Iraq's second largest city of Mosul "in accordance with its Caliphate vision." If ISIS is driven from these cities, it is far from clear that any functional governance will be capable of filling the vacuum.
In any case, American operations against ISIS ultimately help the fledgling governments of both Iraq and Syria.
"[Syrian President Bashar] Assad is the far stronger player in Syria; hitting ISIS necessarily helps him consolidate power," Bremmer noted. "That's a cause and effect that the U.S. is trying to avoid, but it's the reality."