After Saddam Hussein took control of Iraq in 1980, the Arab Socialist Ba'ath Party, Baa'th in common use, because the only political party; removing the problems of Saddam's regime also meant extirpating the leadership of the party, in the process of de-Ba'athification. The term is drawn from the denazification in the occupation of Nazi Germany after WWII.
De-Ba'athification was clearly US policy, but, as with Nazi Germany, it was also recognized that some party members were nonpolitical but had to be members to hold jobs in the nation's infrastructure. There were, however, disconnects between the policy and implementation of de-Ba'athification, and some of the implementation may have contributed to delays in restoring Iraqi infrastructure.
When L. Paul "Jerry" Bremer prepared to leave for Iraq, on May 9, 2003, Donald Rumsfeld had given him a general directive, "The coalition will actively oppose Saddam Hussein's old enforcers — the Ba'ath Party, the Saddam Fedayeen, etc. We will make it clear that the Coalition will eliminate the remnants of Saddam's regime." According to Bremer, Under Secretary for Policy Douglas Feith showed him a more sweeping order, and suggested Bremer issue the order that day. Bremer responded "Hold on a minute, I agree it's a very important step, so important it should wait 'til I get there." Feith emphasized Rumsfeld's directive that it was to be carried out "even if implementing it caused administrative inconvenience." Bremer saw this as potentially more than inconvenience. 
Within the Iraqi political groups, there was no common belief. The INC and Shi'a parties, backed by civilians in the U.S. Department of Defense, wanted the most stringent policy. The Iraqi National Accord and liberals affiliated with Adnan al-Pachaci accepted the most narrow definition. Jay Garner's ORHA did not address it. It was hard to tell what the Kurdish groups wanted, but Bremer, who had the power, was emphatic on a strict process.  Unfortunately, Bremer did not pay attention to the design of the government under Saddam being organized around the party, and structural changes were needed to establish executive groups if there was strong de-Ba'athification. 
On April 16, 2003, GEN Tommy Franks announced the end of combat.  He recommended that only the senior Ba'ath Party leadership be blacklisted, on the assumption, much as with the Soviet Communist Party, that Party members ran most of the basic government services.
Nevertheless, the Party was dissolved on May 12, and CENTCOM was faced with the job of creating a new civilian infrastructure.
LTG (ret) Jay Garner said that he had protested full de-Ba'athification to Bremer, who said "These are the directions I have. I have directions to execute this...""
Garner had experience running humanitarian operations in Iraq after the 1991 Gulf War. Garner said that he always considered himself in a temporary role. He said that Franks had been promised a large number of constabulary from other nations; his immediate goal, before de-Ba'athification, was "...setting up to pay the civil servants and the police and the pensioners. ORHA, however, never really was operational. It was caught, in part, in bureaucratic fighting principally between State and Defense, with some separate positions from Cheney and Rice.
CPA Order Number 1 set up de-Ba'athification. It banned the four “Senior Party Member” top Party ranks, removing them from office and banning them from future public employment, regardless of their role in government or their criminal activities: 
- Udw Qutriyya (Regional Command Member)
- Udw Far (Branch Member)*
- Udw Shu’bah (Section Member)
- Udw Firqah (Group Member) (together, )
are hereby removed from their positions and banned from future employment in the public sector. Further, those of any rank, who held the top three positions in "every national government ministry, affiliated corporations, and other government institutions (e.g., universities and hospitals)." This affected 400,000 military workers and 100,000 civilians. The key problem was in the second category, who might well have had no role in party leadership.
Linda Robinson, a journalist and author of Tell me how this ends: General Petraeus and the search for a way out of Iraq, was invited to discuss the general situation with the U.S. Army Command and General Staff College. She began saying that the insurgency was caused by the early decisions of the US Coalition Provisional Authority for de-Ba'athification and disbanding of the Iraqi military.
Sanchez agreed that the top leadership levels needed to be removed and "those with blood on their hands held accountable and prosecuted. It was the unilateral firing of almost everyone else that created the real problem." Originally, only Bremer himself had the authority to grant exceptions, but, nine days later, he created an Iraqi De-Ba'athification Council reporting directly to him. There were no local-level committees to deal with the "top three positions" in what well might be local organizations.
Further, the Committee was led by Ahmed Chalabi's nephew, whose uncle wanted a total purge of Ba'athists. Sanchez told his commanders to continue with locals in office, "Figure out a best you can what functions we need to establish. Get the best people available and let's get these functions back up and running. And for God's sake, keep the schools open and let the kids finished the school year."
Sanchez contrasted the effort with the denazification of Germany after WWII, where the American military had clear responsibility for policy, planning and implementation. To ensure success, specific goals were set and an effective process was put into place to reach those goals...in this case, the CPA treated the entire endeavor as if they were issuing an academic, theoretical paper."
In the Arabic documents from the CPA, the word used for de-Ba'athification was ijtithaath. Literally, that means "uproot by root and branch", but the connotation was closer to "annihilation or eradication". According to John Maguire of the Central Intelligence Agency station, it reminded Iraqis of the Final Solution. When he told Bremer it was a "heinous word...he blew it off." Maguire said the CIA station was cut out of CPA planning. 
- L. Paul "Jerry" Bremer with Malcolm McDonnell (2006), My Year in Iraq: The Struggle to Build a Future of Hope, Simon & Schuster, ISBN 9780743273893, pp. 39-40
- Ali Allawi (2007), The Occupation of Iraq: Winning the War, Losing the Peace, Yale University Press, ISBN 9780300110159, pp. 147-148
- Allawi, p. 161
- Franks, Tommy & Malcolm McConnell (2004), American Soldier, Regan, pp. 528-529
- , Interview: Lt. General (ret.) Jay Garner"The Lost Year in Iraq", PBS Frontline, Aug. 11, 2006
- L. Paul Bremer (16 May 2003), De-Ba'athification of Iraqi Society, Coalition Provisional Authority
- Linda Robinson (2 December 2008), Remarks to the U.S. Army Command and General Staff College
- Ricardo S. Sanchez with Donald T. Phillips (2008), Wiser in Battle: A Soldier's Story, Harpercollins, ISBN 9780-061562426 pp. 183-187
- Isakoff, Michael & David Corn (2006), Hubris: the Inside Story of Spin, Scandal and the Selling of the Iraq War, Crown, ISBN 0307346811, p. 225