The strategy unveiled by Obama in a national address Wednesday, September 10, envisions local forces trained and armed by the West eventually defeating the well-organized militants in both Iraq and Syria, with the help of a major US-led bombing campaign from the air.
But there are serious questions as to whether the local fighters on the ground – particularly in Syria – would be able to seize and hold territory against the Sunni jihadists, analysts said.
Obama's emphasis on forging local partners comes despite a litany of disappointments over the years when it comes to US attempts to "train and equip" armies, most recently in Iraq.
After years of costly aid and instruction by American officers, the Baghdad government's army suffered a humiliating retreat in the face of the ISIS onslaught earlier this year.
And in Syria, US officials acknowledge that there is no viable "moderate" Syrian opposition at the moment that is capable of holding ground – even after repeated attempts by the West and Arab countries to shape an effective rebel force.
"A strategy predicated on the existence of an effective moderate Syrian rebel force is doomed to fail," said Marc Lynch of the Center for a New American Security,
In Iraq, the West at least has a government it can work with and there is some prospect that Iraqi and Kurdish troops could be shaped into a solid force, Lynch said.
But in Syria, there are no reliable partners in a multi-sided civil war and the overall goal of US military action remains unclear, according to Lynch, associate professor of political science at George Washington University.
"In Syria, by contrast, US air strikes offer no plausible path to political or strategic success," he wrote this week.
Administration officials insist American air power can deliver a serious blow to the jihadists, and open the way to local forces – particularly in Iraq – to roll them back.
They point to the results of more than 150 air strikes in Iraq over the past month, saying the raids have stalled the advance of the jihadists and exposed their vulnerability when confronted by organized military action.
"These insurgent groups, when they try to fight conventionally against advanced militaries, they tend to have significant problems. It's very hard for them to do," said Christopher Chivvis of the RAND Corporation think tank.
"I think there's a lot that air power can do to inflict significant damage on ISIL," said Chivvis, a former senior Pentagon official, using an alternate name for ISIS.
Air strikes proved highly effective in Mali against Al-Qaeda militants, where French warplanes –- backed up by French ground troops – quickly pushed back the extremists last year, he said.
"But this does not mean with air power alone, we will be able to defeat them," he said.
To deal a decisive defeat to any insurgent force, ground troops have to confront them on the battlefield and prevail, he said.
Obama has ruled out deploying ground combat units, allowing only for more military troops to work as "advisers" to the Iraqi and Kurdish forces.
As a result, Washington faces a "big strategic dilemma," Chivvis said.
Air power is not enough, he said, but "if we start using ground forces, especially if they are American ground forces, we risk an international backlash, we risk insurgency, we risk all the problems we faced in Iraq and Afghanistan in the decade after 9/11."
Even if local forces can find their footing, it could take many years to achieve success, Chivvis and other experts said.
With no immediate prospect of a capable Syrian rebel force, air strikes in Syria would have limited results but would "at least make it more difficult for them (ISIS) to resupply their forces in Iraq," said Seth Jones, a former adviser to US special operations forces.
Expanding the air war in Syria, however, carries the risk of unintended consequences, as rolling back the jihadists there could create an opening for President Bashar al-Assad's embattled regime, Jones said.
Washington could soon face calls for more military action in Syria, possibly in aid of more moderate rebels.
"There is a definite danger of escalation in Syria," Jones told Agence France-Presse. "I think it's going to be hard to put the US toe in the water and not be dragged in." – Rappler.com