WASHINGTON — The US has backed itself into a corner by insisting Syrian President Bashar al-Assad be removed from power before the Obama administration will work with Russia and Iran to fight the Islamic State group, former Secretary of Defense Chuck Hagel said.

"We have allowed ourselves to get caught and paralyzed on our Syrian policy by the statement that 'Assad must go,'" Hagel said at a Wednesday event hosted by the Atlantic Council.

Russia and Iran have said they are willing to join with the US in fighting ISIS, but not at the expense of Assad, a longtime regional ally for both nations. The US continues to insist that no serious discussions on working with those two nations can occur until Assad is removed.

But, Hagel said, "there cannot be, will not be, any possibility of resolution or solution until there is a platform of stability. Stability in the sense that it is stable enough, stable enough to start taking it to the next level of trying to sort out what's going on.

"That means working with Russia, clearly," the former secretary continued. "I think it means working with the Iranians. I don't think you will see any possibility of any stability in the Middle East until the Russians, the Iranians, the United States and the Arab nations are part of that."

"Assad is eventually going to have to leave, in my opinion," he added. "That should not hold us captive to everything else."

Hagel's comments come a month after Secretary of State John Kerry appeared to open the door to setting aside the issue of Assad in order to work with Russia against the Islamic State group by saying the US is not seeking "regime change" in Syria; a State Department spokesperson later denied that meant Assad would be allowed to stay.

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The focus on Assad, Hagel indicated, has clouded the situation.

"Assad was never our enemy. A brutal dictator? Yes. There are a lot of brutal dictators out there. I'm not for brutal dictators. But we should have learned from Saddam Hussein and Gadhafi, you can take a brutal dictator out but you better understand what you may get in return," Hagel said. "Let's get to this platform of stability."

Hagel's comments are particularly interesting in light of the revelation, made during an interview with Foreign Policy magazine in December, that the Obama administration was prepared to launch strikes launching strikes against the Assad regime in 2013, after it used chemical weapons.

The strikes were nearly finalized before Obama called them off, despite the statements from top administration officials that the use of chemical weapons by Assad crossed a "red line." By not acting then, Hagel said, Obama cost himself standing around the world.

"It did hurt the credibility of the president of the United States," Hagel said. "When a president of the United States says something, it means something. We Americans, I think, kind of take that for granted, [and say] ‘well the president said this, so what.’ It isn’t that way around the world.

"When a president of the United States says something, especially about something on foreign policy or about another leader of another country, that means something," Hagel continued. "And we have to understand that that means something. And the White House has to understand that means something."

The wide-ranging interview, which was billed as a retrospective of his two year term as secretary of Defense, also revealed Hagel’s view on whether Congress should vote on an authorization of the use of military force, or AUMF.