Spencer Ackerman and Pat Lang both pick up on this Leila Fadel story in the Washington Post:

Hundreds of police officers, formerly members of an American-backed Sunni paramilitary force, will be stripped of their ranks in the Sunni Arab province of Anbar, tribal leaders and Anbar police said Sunday.

[...]

"This committee in the Ministry of Interior is sectarian," said Ahmed Abu Risha, the head of the Awakening and a tribal leader in Anbar. "When you dismiss those who fought al-Qaeda in the streets, this is support for al-Qaeda. What I expect are dire consequences."

Tribal leaders and police officers in Anbar warned that the move could destabilize the province as a political deadlock continues more than six months after national parliamentary elections. They accused the Interior Ministry of demoting them and promoting unqualified outsiders in their stead.

Ackerman gets it mainly wrong when he implies that the U.S. embassy can/should lean on Iraqi Prime Minister Nouri al-Maliki to reinstate the Sunni police. He seems to think that the U.S. government still has enormous leverage over Maliki, and that the Obama administration can somehow heal sectarianism in Iraq.

Lang gets it right. Americans don't have such power. The worst case (a total collapse, full-scale civil war, Iraq as a puppet state of Tehran, etc.) is unlikely, but the rosy best-case scenario spun by COIN advocates simply isn't accurate. Sectarianism persists in Iraq, and it likely will for a long time. The surge didn't solve this problem. Maybe Maliki didn't get that memo?

More to the point, whenever I see stories from Iraq about continued Sunni vs. Shia tension and hostility (and Kurd vs. Arab, too), I am reminded of this infamous comment going back to, appropriately enough, April Fool's Day 2003:

there’s been a certain amount of...pop sociology in America that somehow the Shi’a can’t get along with the Sunni [in Iraq]...There’s almost no evidence of that at all. 
-- Bill Kristol on WHYY/NPR's Fresh Air with Terry Gross.

Right.