What are Obama’s options for defeating the Islamic State?

The Syrian military lost a key air force base to Islamic State (IS) fighters on Sunday, adding to a growing list of land and loot snatched up by the militant group. The base housed several warplane squadrons, ammunition, tanks and artillery.

The IS is strongest in Syria but is better known now in the West for its latest crusade through northern and western Iraq. Earlier this month the U.S. began a limited air campaign to defeat the Islamic State in Iraq, with Barack Obama’s administration saying it needs to protect American interests there. The U.S. has invested close to $2 trillion and nearly a decade of fighting trying to pacify the region.

But with the IS’s stronghold in Syria, focus has shifted toward possible U.S. action there.

“To your question if [the IS] can be defeated without addressing that part of the organization that resides in Syria, the answer is no,” said Chairman of the Joint Chiefs of Staff Gen. Martin Dempsey at a press conference. “That will have to be addressed by both sides — which is essentially at this point a nonexistent border.”

In the Syrian civil war, the U.S. supports a rebel coalition that used to be aligned with the IS in its fight to overthrow Syrian President Bashar al-Assad. Obama has been wary about getting the U.S. militarily involved in that conflict, which has killed more than 190,000 people in the past three years.

But with the IS pushing on in its blaze of destruction along the border between Syria and Iraq, Syria’s Foreign Minister Walid al-Moallem hinted at its willingness to work with the U.S. to take down the IS.

“I assure you that Syria is ready to cooperate and coordinate on regional and international levels to fight terrorism,” he said on Monday. “But taking into consideration that the Syrian government is representing Syrian sovereignty, any effort to combat terrorism should be coordinated with the Syrian government.”

Siding with a regime that the U.S. has encouraged others to overthrow doesn’t sound ideal or even logical, but what other options does the U.S. have? Can the U.S. defeat the IS without giving an advantage to other problematic players in the region?

We discussed it with a panel of experts on this edition of “Inside Story.”