I'm certainly no prophet, since anyone with a pulse could have predicted this -

But I have in the past stated that just such a thing would occur:

Members of United States-allied Awakening Councils have quit or been dismissed from their positions in significant numbers in recent months, prey to an intensive recruitment campaign by the Sunni insurgency, according to government officials, current and former members of the Awakening and insurgents. 

Although there are no firm figures, security and political officials say hundreds of the well-disciplined fighters — many of whom have gained extensive knowledge about the American military — appear to have rejoined Al Qaeda in Mesopotamia. Beyond that, officials say that even many of the Awakening fighters still on the Iraqi government payroll, possibly thousands of them, covertly aid the insurgency.

The defections have been driven in part by frustration with the Shiite-led government, which Awakening members say is intent on destroying them, as well as by pressure from Al Qaeda. The exodus has accelerated since Iraq’s inconclusive parliamentary elections in March, which have left Sunnis uncertain of retaining what little political influence they have and which appear to have provided Al Qaeda new opportunities to lure back fighters.

NYT