After the 2003 invasion of Iraq was completed and the regime of Saddam Hussein was toppled in May 2003, an Iraqi insurgency began that would last until the United States left in 2011. The 2003–2006 phase of the Iraqi insurgency lasted until early 2006, when it escalated from an insurgency to a Sunni-Shia civil war, which became the most violent phase of the Iraq War.
Background
Build up to insurgency
A number of factors played into the beginning of the insurgency in Iraq. Invading U.S.-led forces were unable to immediately fill the power vacuum caused by the sudden collapse of a highly centralized state authority, resulting in weeks of virtual anarchy. Due to the fact that Saddam Hussein terrorized his military and time constraints in the planning of the invasion on the United States' side a power vacuum was created once the invasion started. This was due to the fact that Iraqi soldiers abandoned areas before U.S. forces could reach them and the fact that the United States failed to draw up plans on what to do once Saddam had been removed from power. The inability of American-led forces to control the situation, led to Iraqi resentment. Additionally, the unexpectedly quick implosion of Saddam's regime meant that the invading forces never engaged and decisively defeated his military in any major battle; the Iraqi armed forces simply dispersed, often with their weapons, back to their homes. At least part of the reason for this was that the Iraqi military and the security services were disbanded, after the invasion by U.S.-led forces, a decision taken by the U.S. ambassador Paul Bremer. Another cause of resentment was the lack of immediate humanitarian aid and reconstruction efforts for Iraqis suffering from the invasion, the long-term effects of the repression and mismanagement of the Saddam regime, and international sanctions. A number of factions felt suspicious of long-term American intentions; the conduct of some American soldiers also served to heighten tensions. The de-Ba’athification Commission set up by the Coalition Provisional Authority, the nature of selection of the Governing Council, and other policy decisions were interpreted by Sunni Arabs as actions intended to single out their community for discrimination; this encouraged the beginnings of sectarian tensions. However, before the invasion sectarian tensions already existed in Iraq, due to the inherent inequalities between those communities during Saddam's regime.
Members of insurgent groups came from a variety of sources. Former members of the security services of the Ba’ath regime, former military officers, and some other Ba’ath Party members are cited as members of insurgent groups; indeed, these elements formed the primary backbone of the nascent insurgency. Initially, most former members of the Ba'ath Party and former Iraqi soldiers expressed a willingness to compromise with the Coalition forces. However, many lost their jobs and pensions with the disbanding of the Iraqi army by Bremer; this, and the unwillingness of the Coalition Provisional Authority to negotiate with former Ba'ath elements, provided impetus for the initial insurgency. While 80% the officers were Sunni, the rank and file of the regular army was 80% Shia. Prisoners released from prison by Saddam before his disappearance provided another source both of insurgent recruits and of organized crime factions. Finally, as O’Hanlan says, the porous borders of Iraq and the subsequent foreign insurgents also bolstered the insurgency.
History
Insurgency begins (April–June 2003)
In April 2003, after the Iraqi conventional forces had been defeated and disbanded, the U.S. military noticed a gradually increasing flurry of attacks on U.S. troops in various regions of the so-called "Sunni Triangle", especially in Baghdad and in the regions around Fallujah and Tikrit. These consisted of small groups of suspected guerrillas firing assault rifles and rocket-propelled grenades, in addition to using basic forms of IEDs (Improvised Explosive Device) on U.S. patrols and convoys in attacks that were often poorly planned and demonstrated poor marksmanship and training. In many cases, the insurgents were killed in the return fire. The U.S. military blamed the attacks on remnants of the Ba'ath Party and the Fedayeen Saddam militia. It seems that many of these attacks were "potshots" from disaffected former members of the Iraqi military. Tensions between U.S. forces and the residents of Fallujah were especially severe, with crowd riots and small skirmishes commonplace.
Coalition response and counterinsurgency (June–September 2003)
In response to the attacks taking place, on June 9, the U.S. military launched Operation Peninsula Strike, in which 2,000 soldiers from Task Force Iron Horse swept through the Tigris River peninsula of Thuluiya in the Sunni Triangle, detaining 397 Iraqis. Almost all of the detainees were later released, and the operation failed to stem the tide of the assaults. A series of similar operations were launched throughout the summer in the Sunni Triangle, such as Operation Sidewinder, Operation Soda Mountain, and Operation Ivy Serpent. One, known as Operation Desert Scorpion, succeeded in destroying an encampment of over 70 local fighters, possibly linked to the Fedayeen Saddam, near the Syrian border town of Rawa.
However, these initial counterinsurgency efforts failed to suppress the insurgency. The sweeps failed to stem the tide of the attacks, which during the summer of 2003, numbered about a dozen a day and resulted in, on average, one U.S. soldier killed and seven more wounded every day. The guerrillas began adopting new and more complex tactics, such as the planting of IEDs (concealed bombs usually placed on the roadside), the use of mortars, and better-planned ambushes. Although some humanitarian operations were included in what was intended to be a "carrot and stick" strategy, the cordon and search operations are widely criticized for being far too blunt and not carefully targeted. The large numbers of innocent Iraqis detained during the raids, the removal of palm trees and other foliage to deprive guerrillas of cover for ambushes (and which represented the livelihoods of many farmers) and the failure to restore basic services such as water and electricity to pre-war levels began increasing the nationalist resistance among the Sunnis and began resulting in the disillusionment of an Iraqi populace. In addition, as the summer neared its end, a series of suicide bombings began that suggested an increasing Islamist terrorist threats. The Canal Hotel bombing targeting the UN on August 19, and the massive blast at the Imam Ali Shrine that assassinated Ayatollah Mohammed Baqir al-Hakim along with dozens of others. Only ten days later marked the beginning of another phase to the conflict.
An effort began in August by the coalition to increase human intelligence gathering in order to more carefully target operations. The effort did eventually begin to reap limited and temporary results in the north-central region of the country (which includes Tikrit and up to the southern borders of Mosul and Kirkuk), as informants guided troops over the next six months to hideouts and weapons caches primarily belonging to the Fedayeen Saddam and the remaining Ba'athist resistance. However, most of the Sunni regions saw the military situation gradually worsen for the U.S. as a disaffected nationalist resistance began to take hold.
Ramadan Offensive (October–November 2003)
In October 2003, the intensity and pace of insurgent attacks began to increase. Finally, at the end of October, a series of four simultaneous suicide car bomb attacks on the Iraqi police and the International Red Cross, quickly followed by a sharp surge in guerrilla attacks, ushered in an insurgent effort that was termed the "Ramadan Offensive," as it coincided with the beginning of the Muslim holy month of Ramadan. Attacks that were increased to nearly 50 a day, along with a series of helicopter downings, resulted in a U.S. death toll of 82 for the month of November with 337 wounded in action.
Operation Iron Hammer (November–December 2003)
In response, the coalition launched its counteroffensive known as Operation Iron Hammer in the second week of November. Operation Iron Hammer brought back the use of U.S. air power for the first time since the end of the initial war to topple Saddam's regime, with suspected ambush sites and mortar launching positions struck from the air and with artillery fire. Surveillance of major routes, patrols, and raids on suspected insurgents were stepped up. In addition, two villages, including Saddam's birthplace of al-Auja and the small town of Abu Hishma were wrapped in barbed wire and carefully monitored. Following Operation Iron Hammer, the number of insurgent attacks dropped to an average of 18 a day. In the wave of intelligence information fueling the raids on Ba’ath Party members connected to insurgency, Saddam himself was captured on a farm near Tikrit on December 12, 2003. This apparent renewed success led many to a renewed sense of optimism that the U.S. was prevailing in the fight against the insurgency.
January–March 2004
The period from December 2003 to March 2004 marked a relative lull in guerrilla attacks. It is believed that although some damage was done to the insurgency, this was primarily due to a reorganization period during which new U.S. tactics were studied and a renewed offensive planned. Although the guerrilla attacks were less intense, the "terrorist" offensive, possibly connected to the followers of Abu Musab al-Zarqawi, only increased. Hundreds of Iraqi civilians and police (mainly Shi'a) were killed over this period in a series of massive bombings. These events marked the emergence of the organization then known as Jama'at al-Tawhid wal-Jihad, led by al-Zarqawi, to prominence as a major force within the insurgency. This organization, composed both of foreign fighters and Iraqis, had a militant Sunni Islamist agenda.
Spring 2004 uprising
Resistance to U.S.-led forces would not for long be confined to the Sunni regions of Iraq. Over this period, Shiite dissatisfaction with the occupation, especially among the urban poor, had been gradually increasing for some of the same reasons it had been among the Sunnis: the perception that the coalition had failed to deliver on its promises and a nationalist dissatisfaction with foreign occupation. Many young men without jobs or prospects and who had lost faith with the promises of the U.S. began to become drawn to Shiite religious radicalism, especially of the brand advocated by the cleric Muqtada al-Sadr. Sadr's distinguished family background, and his fiery anti-occupation rhetoric and calls for the implementation of Islamic law, caused him to emerge as the leader of this portion of Iraqi Shiite society. In June 2003, after being rejected from a spot on the Iraqi Governing Council, he had created a militia known as the Mahdi Army, whose mission he said was to help keep order and cleanse Iraq of "evil." Since that point, the U.S. had regarded him as a threat, but was divided on whether or not to proceed with a crackdown. Eventually, as Sadr's rhetoric heated and his militia paraded through Sadr City in what seemed like a challenge to the United States, they decided to begin to squeeze his movement. On March 29, they moved to close Sadr's newspaper known as al-Hawza and arrested one of his aides on murder charges. That, combined with his steadily decreasing political prospects for success within the U.S.-backed interim government, pushed Sadr to decide for armed revolt.