There is no security in Iraq.

BAGHDAD, Iraq - Gunman abducted about 85 workers Wednesday as they left an industrial plant north of Baghdad, police and a witness said. The workers were thought to be mostly Shiite and the plant is located in a predominantly Sunni Arab area.

This isn't just some small scale drive-by shooting or IED, this is a major operation, and it's this type of massive violence that undermines the legitimacy of the Maliki government. If the government of Iraq cannot protect the people from this sort of violence, the rank and file "true" civilians in Iraq have little choice but to turn to their various factional militias for protection.

The Maliki government is on the knife's edge right now, and it's looking more and more possible that it may go the Afghanistan route where President Karzai has so little influence he is derisively called "the mayor of Kabul."

It's hard to call at this point, but whatever credibilty the Iraqi government has in the area of security is being quickly spent.

(By the background of this, Shia workers in a predominant Sunni area, I would guess this is more activity by the new claimant to Zarqawi's title, although at this point there's no way to tell.
Taji, you might remember from the series Off to War, is the location of a major US base.)