In November 2008 an agreement that determined a timetable for the final withdrawal of U.S. forces, which had been under negotiation for nearly a year, was approved by the Iraqi parliament. Under that agreement, U.S. troops were scheduled to leave the cities and towns by mid-2009, and withdrawal from the country was set to be completed in early 2012. In February 2009 newly elected U.S. Pres. Barack Obama announced that U.S. combat forces would be withdrawn from Iraq by the end of August 2010, with the remaining troops due to pull out by December 2011. On June 30, 2009, after turning security responsibilities over to Iraqi forces, U.S. troops completed their withdrawal from the country’s cities and towns as scheduled.

In October 2011 the United States announced that the last of its 39,000 troops would leave Iraq at the end of 2011. On December 15 the U.S. military held a ceremony in Baghdad to formally declare the end of its mission in Iraq, and the final U.S. forces departed before the end of the year.

Second term of Prime Minister Nouri al-Maliki and sectarian polarization

The withdrawal came at a difficult time in domestic politics. Parliamentary elections held in March 2010 proved indecisive as to who would control the government. Former prime minister Allawi’s secular coalition won 91 seats, more than any other group, but only narrowly defeated Prime Minister Maliki’s coalition, which secured 89 seats in the election. Even before results were released, Maliki requested a recount, which was denied; after the results were released, he continued to mount legal challenges to Allawi’s apparent victory, resulting in a power struggle that left Iraq without a government for much of 2010. Maliki’s position was strengthened in October 2010 when the coalition led by Sadr, in a reversal, nominated Maliki for a second term as prime minister.

In November 2010, after an eight-month political stalemate, Iraq’s major political parties entered a power-sharing agreement that paved the way for a national unity government. Allawi’s coalition agreed to join the Maliki government, with Maliki remaining prime minister and with a member of Allawi’s coalition becoming the speaker of the parliament. In December a new cabinet was sworn in, although no ministers were appointed for the defense, interior, and national security ministries, as the parties had been unable to negotiate an agreement regarding the heavily contested security portfolios. Maliki was made acting head of each of those ministries until a compromise could be reached. However, the power-sharing agreement soon proved unworkable; factional struggles over oil revenues and the control of government institutions continued. Maliki’s critics accused him of undermining the agreement by retaining near-exclusive control of the security forces.

In February 2011, protests erupted in parts of Iraq amid a wave of popular uprisings that spread throughout the Middle East and North Africa (see Arab Spring). On February 25, thousands of demonstrators took to the streets in Iraq to protest the country’s high unemployment rate, corruption, and insufficient public services. Iraqi police responded aggressively, attempting to disperse protesters with water cannons and in some cases live fire. There were also reports that journalists had been detained and beaten by security forces. The protests caused several provincial governors to step down from their posts. In the aftermath of the demonstrations, Maliki announced new initiatives to meet protesters’ demands, including measures to ensure greater government accountability and fight corruption.

Iraq’s factional stalemate persisted, hindering reconstruction efforts and threatening to push the country back into sectarian conflict. Maliki’s critics continued to accuse him of exercising personal control over the ministries of defense, the interior, and national security and of using the forces at his disposal to punish his political and sectarian rivals. Just days after the U.S. withdrawal, an arrest warrant was issued for Tariq al-Hashimi, the Sunni vice president, for having allegedly commanded a death squad during the war. Hashimi fled to the Kurdish autonomous region, beyond the reach of the central government’s security forces, and then on to Turkey. Sunni politicians denounced the accusations against Hashimi as part of a campaign by Maliki to exclude Sunnis from political participation and staged a monthlong boycott of the Council of Representatives. Sunni representatives then tried to arrange a vote of no confidence in Maliki, but the effort ultimately fell short. Hashimi was convicted in absentia and in September 2012 was sentenced to death.

In the provinces Al-Anbār, Nīnawā, and Ṣalāḥ al-Dīn in western and northern Iraq, Sunnis staged anti-Maliki protests after 10 bodyguards of the Sunni finance minister Rafi al-Issawi were arrested in December 2012. Security forces’ largely self-defeating attempts to suppress the protests culminated in a raid on a Sunni protest camp in the city of Ḥawīja in April 2013 that killed approximately 40 civilians. The aggravation of sectarian tensions translated into increased violence: bombings by Sunni extremists targeting Shiʿis and the government once again became a regular occurrence, and civilian deaths rose significantly for the first time since the height of the war in 2006–08.

Fight against ISIL

Radical Sunni militants in western Iraq benefited from the presence of similar Sunni groups fighting in the Syrian Civil War, and weapons and fighters flowed back and forth across the Iraq-Syria border. In April 2013 al-Qaeda in Iraq and some radical elements of the Syrian opposition began operating jointly under the name Islamic State in Iraq and the Levant (ISIL; also known as the Islamic State in Iraq and Syria [ISIS]).

By late 2013 ISIL had begun to pose a serious challenge to the Iraqi government’s control in western and northern areas of the country. In January 2014 ISIL took control of the predominately Sunni city of Fallujah and parts of Al-Ramādī, the capital of Al-Anbār. In mid-June the confrontation between Sunni militants and the government reached a crisis point when ISIL fighters seized the northern city of Mosul, the second largest in Iraq, meeting little resistance from security forces. Fighters then moved south, overrunning Tikrīt. Images that appeared to show ISIL gunmen executing large numbers of captured Iraqi soldiers circulated on social media after the takeover.

The inability of the Iraqi security forces to defend against the onslaught of ISIL that June highlighted their inadequacy, while a number of militias seemed better prepared to take on the insurgents. Shortly after ISIL’s capture of Mosul, many of these militias were formally recognized and supported by the Iraqi government under the umbrella of the Popular Mobilization Forces (PMF; also called al-Hashd al-Shaabi). Days later Grand Ayatollah Ali al-Sistani, one of Iraq’s most popular Shiʿi clerics, called on his followers to join the PMF in the fight against ISIL. Thousands of Iraqis heeded the call, and the PMF began leading the fight to turn back ISIL from its southward advance.

Meanwhile, the ISIL takeover posed a grave threat to minority communities in northern Iraq. Reports of ISIL fighters seizing non-Muslims’ property were widespread, and there were some reports of kidnappings and murders. In many areas under its control, ISIL circulated decrees threatening non-Muslims with death if they refused to convert to Islam or pay the jizyah, a special tax traditionally demanded by Muslim rulers from non-Muslim subjects. Christians, Yazīdī, and Turkmens fled their homes en masse; many were forced into uninhabited areas without access to food or water.

In early August ISIL forces captured several towns and a major dam on the outskirts of the autonomous zone controlled by the Kurdistan Regional Government (KRG). On August 8 the United States began to launch limited air strikes against ISIL to prevent it from advancing farther into Kurdish territory. KRG forces, known as the peshmerga, were able to drive out ISIL from some areas—including areas that were beyond the autonomous zone borders, such as the lucrative oil-producing city of Kirkūk—and then held the reclaimed territory as part of the Kurdish autonomous region.

The ISIL crisis eroded support for Maliki, whose sectarian approach to governing was seen as a major factor in the alienation of Sunnis. Although Maliki’s State of Law coalition had won the largest number of seats in parliamentary elections in April 2014, paving the way for Maliki to claim a third term as prime minister, he soon found himself resisting pressure from former supporters both inside and outside Iraq to step aside in favour of a less-divisive figure. The nomination in early August of Haider al-Abadi, another member of the State of Law coalition, to form a new cabinet seemed to signal that Maliki’s efforts to retain power were doomed. Indeed, Abadi was installed as prime minister on September 8, 2014, and was able to form an inclusive administration. Efforts by Iraqi forces to expel ISIL from Iraq, with the support of a U.S.-led coalition, continued under Abadi, with the group finally being pushed out of most of the country by the end of 2017.

Meanwhile, in September 2017, KRG officials held a nonbinding referendum on independence in the area under KRG control; it was overwhelmingly approved with more than 92 percent of the vote. The referendum, however, found very little international support, many countries having urged the KRG not to proceed with it in order to avoid further exacerbating the already unstable nature of the region. The Iraqi central government was strongly opposed to the referendum. Within weeks of the vote, the government sent troops to the areas outside the KRG’s borders that were claimed by both the central government and the KRG, resulting in clashes between the two sides. Iraqi forces quickly retook Kirkūk as well as other disputed areas outside the Kurdish autonomous region. Tensions between the two sides were reduced somewhat in March 2018 by the progress of ongoing negotiations.