Updated 10:00 p.m. | President Barack Obama has the authority to wage war in Iraq without going to Congress, because the original use of force authorization remains in effect.  

Obama said Thursday he’s “not ruling anything out” in Iraq, as rebels have swept through some of that country’s largest cities and are bearing down on Baghdad.  

But White House Press Secretary Jay Carney appeared to walk back Obama’s comment at his briefing.  

“We are not contemplating ground troops. I want to be clear about that. The president … was answering a question about airstrikes,” Carney said.  

When asked about getting Congress’s permission to take action, Carney was noncommittal.  

“We are in active consultation with members of Congress,” he said.  

He demurred when asked directly about the 2002 authorization to use military force (AUMF). An administration spokeswoman, Caitlin Hayden, told Yahoo’s Olivier Knox in January “the administration supports the repeal of the Iraq AUMF.” Hayden emailed CQ Roll Call late Thursday and to reiterate that what she said then remains in effect.  

She declined to comment on what authority Obama would have to act if he decided to launch a strike.  

“We support it’s repeal for all the same reasons as before, without commenting on decisions the President hasn’t made yet,” she said in an email.  

Some Capitol Hill sources believe Obama could still act using other authorities, including the broad war on terror AUMF passed by Congress after the Sept. 11, 2001, attacks, even if the Iraq AUMF is repealed. Obama has used that authority for drone strikes in a number of countries.  

A recent Congressional Research Service report says the AUMF in Iraq had no expiration date and has not been repealed. Therefore it remains current law, “although its continued effectiveness is questionable.  

“Arguably, the president could rely on [it] to reintroduce forces into Iraq if he determined that Iraq once again posed a threat to U.S. national security.”  

But, the report notes, any such decision would likely meet renewed opposition in Congress.  

Another military involvement in Iraq would be certain to face resistance from the president’s own party.  

Several lawmakers urged caution before taking action, including Senate Armed Services Chairman Carl Levin, D-Mich.  

“We got into Iraq without adequate consideration for the consequences,” he said in a Thursday statement. “What is required now is thoughtful consideration of our options, none of which, typically for the Middle East, is obvious or easy. … It’s unclear how air strikes on our part can succeed unless the Iraqi army is willing to fight, and that’s uncertain given the fact that several Iraqi army divisions have melted away. While all options should be considered, the problem in Iraq has not been so much a lack of direct U.S. military involvement, but a lack of reconciliation on the part of Iraqi leaders.”  

Just last month, Democrats led by Foreign Relations Chairman Robert Menendez of New Jersey introduced legislation to repeal the Iraq authorization.  

“The time to repeal the authorization for use of military Force for Iraq is past due,” Menendez said then. “Our service members completed their mission with distinction and courage when combat operations ceased in 2010 and the U.S. Congress must fulfill its obligation and repeal the AUMF. I voted against the Iraq War, and now, after nearly 5,000 of our bravest American souls paid the ultimate sacrifice for their country, we have a responsibility to formally end this state of conflict and rescind this open-ended AUMF for Iraq.”  

Other Democrats signed on, including Sens. Barbara Boxer of California, Benjamin L. Cardin of Maryland and Tim Kaine of Virginia.  

“Voting against the resolution authorizing the use of military force in Iraq was one of my proudest moments as a senator,” Boxer said as the bill was introduced. “It is long past time to close this tragic chapter in American history.”  

But by Thursday, Boxer appeared to change her tune, saying the United States should “go after” the rebels.  

“Much American blood was spilled during the Iraq War and while I believe we should go after ISIS-which poses a threat to the entire world-any U.S. action must be well-considered and well-executed in coordination with our allies and the Iraqi government and military, which we helped train and arm,” she said in a statement. “Iraq should know that it needs a unity government now or its future will be bleak.  

“Some of the biggest GOP cheerleaders for the disastrous war in Iraq are now joining the blame-America-first crowd rather than working with our Commander-in-Chief to confront this crisis.”