As Sunni rebels from an al Qaeda splinter group drive Iraq deeper into chaos, calls for American intervention are growing louder amid fears the trouble could spread beyond the nation's borders.
"This is a really bad situation strategically. The American people are tired of two wars. I am, too, but you can't just let this thing go into free fall," said retired U.S. Army Gen. Montgomery C. Meigs.
Iraq has asked the U.S. for air assistance in tempering the militant uprising. President Barack Obama said Thursday he is looking at all options in confronting the Iraq insurgency, but he did not specify what type of help he would be willing to provide.
"I do not rule out anything, because we do have a stake in making sure these jihadists are not getting a permanent foothold in either Iraq or Syria," he said, adding that "what we've seen over the last couple of days indicates the degree to which Iraq is going to need more help."
The militants from the Islamic State in Iraq and the Levant, also called ISIL or ISIS, chased government forces out of Tikrit on Wednesday and then closed in on Iraq's biggest oil refinery at Baiji, furthering their rapid gains against the Shiite-led government.
A day earlier, the al Qaeda affiliate overran Mosul, Iraq's second-largest city, and on Thursday, an audio recording purported to be from the spokesman of ISIS urged fighters to take over Baghdad next.
The developments have prompted leading Republicans to call for immediate action. Sen. Lindsey Graham, R-S.C., voiced security concerns, urging U.S. involvement as militants turned sights on the capital.
“I have never been more worried about another 9/11 than I am right now,” Graham said.
Sen. John McCain, R-Ariz., echoed that worry, calling this "the gravest threat to our national security since the end of the Cold War."
A 'likely outcome'
The Sunni fighters are trying to establish an Islamic emirate that would stretch across the border of Iraq and Syria, prompting fears of a sectarian bloodbath and a regionwide conflict.
Meigs and other experts say that while the chaos ensuing in Iraq now wasn't necessarily an inevitable effect of the U.S. troop withdrawal in 2011 after eight years of occupation, it was "a danger, a relatively likely outcome."
Calls are growing on U.S. officials to respond — at the minimum, to put pressure on Prime Minister Nouri al-Maliki. When the U.S. withdrew forces, it lost any leverage it had over al-Maliki, said Stephen Biddle, a George Washington University professor and adjunct senior fellow at the Council on Foreign Relations.
"In Iraq, everybody left all of a sudden at the end of 2011. And the result has been kind of what you'd expect in situations like this," he said. "The sectarian populations that are still scared to death of each other have continued to have their fingers on the triggers, on the constant lookout for slights or violence or indications of hostile intent from the other."
Al-Maliki is accused of stripping Sunnis of power in Iraq and oppressing them, one of the main drivers for stunningly quick military action from the Sunni ISIS rebels. In neighboring Syria, ISIS, which broke from al Qaeda's international leader, Ayman al-Zawahri, has also clashed with al Qaeda fighters.
"There's no doubt that al-Maliki has alienated Sunnis in Iraq," terrorism analyst Evan Kohlmann said Thursday on MSNBC. "It's scary to see this, but let's remember this all occurred because they are losing in Syria. They are suffering defeats in Syria. That's what's causing this."
And as frightened Sunnis in Iraq came to view al-Maliki's government less as politicians and more as a Shiite militia, ISIS was able to gradually build up strength, picking up Sunnis who wanted to maintain control over their communities, said Biddle.
The problem, he said, could have been avoided had the U.S. kept peacekeepers in Iraq instead of withdrawing entirely — similar to what it did in the Balkan crisis of the 1990s.
"What stabilized the Balkans was an extended presence by foreign peacekeepers who were able to dampen these escalatory spirals, reassure everybody that the local other wasn't trying to slaughter them, and keep the temperature down while the gradual experience of living together without getting slaughtered enabled slow re-emergence of co-existence," he said.
No choice but to intervene?
While it's too late for that, the U.S. can still dangle the offer of military support over al-Maliki.
"If he decides that the United States military is his own route to survival, then we might suddenly have some leverage over him by either offering military support if he agrees to clean up his act politically and accommodate Sunnis, or denying him that support if he won't," Biddle said.
Obama referred to the politics inside Iraq on Thursday, saying, "This should be a wake-up call to the Iraqi government that there has to be a political component to this ... and that requires concessions on part of Shi'a and Sunni we haven't seen so far.”
The threat of violence expanding was enough for politicians and analysts to call for U.S. airstrikes in Iraq on Thursday.
"There is no scenario where we can stop the bleeding in Iraq without American air power," Graham said.
Kohlmann, the terrorism analyst, said the U.S. had no choice but to get involved, through airstrikes or some other method.
"This is now a question of U.S. national security," he said.
Quelling the violence is considered central to protecting the broader Middle East, where Persian Gulf oil exporters could face serious problems if the region falls into conflict.
"If the situation in Iraq gets really fouled up and the worst case scenario emerges, you could have a problem much bigger than Iraq and much bigger than Syria," Biddle said. "It could end up sucking in the entire energy export system of the Middle East, with important consequences for the global economy and U.S. national security."