Defense Secretary Ash Carter's blunt assessment that Iraqi forces lack the "will to fight" undermines a central premise of President Barack Obama's strategy for defeating the Islamic State of Iraq and al-Sham (ISIS): that Iraq's military can effectively handle ground operations so Americans don't have to. Carter's comments in a weekend interview reflect deep concern within some quarters of the administration about the capabilities of Iraq's security forces. Despite outnumbering ISIS forces, the military suffered a major defeat this month in the city of Ramadi. And some officials question whether it can overcome the same sectarian divisions between Sunnis and the Shiite-dominated government that gave the ISIS space to thrive. "The failure, it's not one of courage," Marina Ottaway, a Middle East analyst at the Wilson Center, said of the Iraqi military. "It's one of politics."

For now, Obama is showing no sign of significantly shifting his strategy or easing his opposition to sending American forces back into combat in Iraq. Instead, the White House is essentially pleading for patience and even more time to train Iraqis.

"That's a training process that can't be done in a week," White House spokesman Josh Earnest said Tuesday. "That's not a seven-day training course. This is going to require a more sustained commitment."

The U.S. already has spent years and billions of dollars trying to position the Iraqi military to take charge of the country's security. As the U.S. military withdrew from Iraq in 2011 after more than eight years of war, Obama declared that local forces were indeed ready to take on that mission.

With a fresh infusion of American trainers last year and a new Shiite government pledging to be more inclusive to Sunnis, Iraqi forces had made apparent progress against ISIS in recent months. But the rout in Ramadi, the strategically important capital of Anbar province, highlighted the military's weakness anew. Fleeing the city, Iraqi forces abandoned U.S military vehicles, including tanks, armored personnel carriers and artillery pieces. "What apparently happened is the Iraqi forces just showed no will to fight," Carter said Sunday on CNN. "They were not outnumbered. In fact, they vastly outnumbered the opposing force. That says to me, and I think to most of us, that we have an issue with the will of the Iraqis to fight ISIL and defend themselves." His comments echoed Joint Chiefs Chairman Gen. Martin Dempsey, who said the Iraqi security forces were "not driven out of Ramadi. They drove out of Ramadi." Iraqi officials disputed Carter's characterization of the military's strength, saying he had received "incorrect information." Vice President Joe Biden called Prime Minister Haider al-Abadi in an apparent attempt to ease his concerns about the U.S. commitment to his security forces, while administration officials quietly tried to clarify the Pentagon chief's comments. On Tuesday, the Iraqi government announced the start of a major military effort aiming to drive ISIS from western Anbar province. The operation involved Iranian-backed Shiite militias, sparking fears of potential sectarian violence in the Sunni heartland.