From the Washington Post:
The very setup of the U.S. presence in Iraq undercut the mission. The chain of command was hazy, with no one individual in charge of the overall American effort in Iraq, a structure that led to frequent clashes between military and civilian officials.
On May 16, 2003, L. Paul Bremer III, the chief of the Coalition Provisional Authority, the U.S.-run occupation agency, had issued his first order, “De-Baathification of Iraq Society.” The CIA station chief in Baghdad had argued vehemently against the radical move, contending that, “By nightfall, you’ll have driven 30,000 to 50,000 Baathists underground. And in six months, you’ll really regret this.”
He was proved correct, as Bremer’s order, along with a second that dissolved the Iraqi military and national police, created a new class of disenfranchised, threatened leaders.
Here.