ISIS: How to 'degrade and destroy' the militant group

By vowingto "degrade and destroy"the Islamic State militants, U.S. President Barack Obama has laid out a goal thatwill certainly face a series of daunting challenges and could take years to accomplish.

"Degradingis relatively easy," said Austin Long, assistant professor of international and public affairs at Columbia University and a former adviser to the multinational force in Iraq, "It's the destruction part thats very difficult."

• Obama vows to 'degrade' ISIS after beheading video
• ISIS by the numbers:How rich the militants may be
• Obama's dilemma: Would airstrikeshelpAssad in Syria?

"You can continue with airstrikes.That would certainly be effective over time at degrading the organizationover time, particularly as your intelligencepicture gets better," Long said. "But theres a real limit,particularly on how much damage you can do to an organizationthat is well institutionalized and as large as ISIS."

ISIS is thoroughly embedded in northern and eastern Syria and northern and western Iraq.It has thousands of combat-experienced fighters, is very well financed andwell armed, and gains more adherents every day,said PeterMansoor, the former executive officer to then general DavidPetraeusduring the period of the Iraqi surge in 2007 and 2008

"So its not going to be an easy group to destroy, and it'lltake a number of years to do so, absent direct involvement from U.S. ground forces, which is not in the cards," Mansoor said.

But Colin Clarke, an associate political scientist who specializes in insurgency and transnational terrorism at the RandCorporation, said the most realistic goal should be containment, not destruction.

'Weaken, not obliterate'

"It should be enervate, to weaken, not obliterate," Clarke said. "It think that'snot only more realistic but it's more achievable."

"Im not sure you could actually ever really fully extirpate it," he said. "It's really about reducing it from a major challenge to a regional nuisance."

Clarke, along with Christopher Paul, wrotePaths to Victory: Lessons from Modern Insurgencies,a study of 71 counterinsurgencies since the end of the Second World War. In apiece for the Washington Post, both Clarke and Paul said the U.S would need toovermatchthe insurgency, something continued airstrikes would help accomplish. But it also musthone in on ISIS's operational tools money, weapons, intelligence, training and sanctuary as well as the group's organizational tools:leadership, ideology, media recruitment and organizational structure.

Part of the strategy to combat ISIS would involve engaging in a hybrid war,one that combines conventional and irregular forces fighting together, Mansoorsaid.

The Iraqi army would need to be rebuiltinto a competent fighting force, while the KurdishPeshmergaforces would also need to be armed, trained and advised, all ofwhich could take oneto twoyears.

Training the Kurds, who have been seen as an effective force against ISIS, would take less time. However, the issue with the Iraqi army is leadership, Mansoor said, and it will take time to vet new leaders.

Around10,000 to 15,000 U.S. troops would be needed in an advisory capacity, Mansoor estimated. But he added that hundreds of U.S. special forces troops would be needed on the ground to help call in airstrikes and make those attacks more effective, meaning that some American soldiers "would be in the thick of it."

• What Canada could offer if West decides on military action
• ISIS: 5 things to know about the Iraqijihadistgroup

But thatentire strategy is all predicated onthe creation of a government in Baghdad that all sects,ethnicities and factions in Iraq can support, analysts say. Getting co-operation from theSunnis, whofor years weredisenfranchized by the Nouri al-Maliki government, would be crucial to any kind of success. Yet withal-Maliki having recentlystepped down as Iraqi prime minister, there's renewed hope that the newgovernmentwould be more inclusive.

"Absentthat I don't think any strategy will succeed," Mansoor warned.

The challenge of Syria

Syria poses another huge challenge, and a bit of a conundrum. The White House doesn't want to inadvertently be in a positionof of directly or indirectly helping the Assad regime, but in order to do damage to ISIS, the U.S. will need to be able to strike in Syria.

"So how do you balance thoseobjectives?" Long said.

One route is to arm and boost up the Free Syrian Army, seen as a relatively moderate group among the rebels fighting the Syrian government. But, as Mansoor observed, the group is currently"pretty much a wet noodle" in terms of strengthand could take years to get into fighting form.

Regionalco-operationwould also be key.Mansoorsuggested thatJordan and Turkeycouldprovide bases for aircraft andspecial forces.But building such a coalition wouldn't be easy when it comes todetermining what countries join and what roles they play.

"The region is still in flux and the dust really hasn't settled from the Arab Spring," Clarke said.

As well, the U.S need only turn to their recent military incursions toshowthe difficulties of defeating such groups.

"The U.S had over 100,000 troops on the ground in Iraq at on point andwas conductingan all out offensive against ISIS predecessor al-Qaeda in Iraq and wasnt capable of completely destroying it," Long said. And the Taliban in Afghanistan has been "degraded, degraded and degraded," yet it continues to rebuild.

"These campaigns can be quite open-ended even though you caninflictdamage quite quickly," he said. "So destroyingorganizationslike ISISis goingto be extremely challenging."