Iraqis have persevered through intermittent wars, internal conflicts, sanctions, displacements, unrest, and terrorism for decades. A 2003 U.S.-led invasion ousted the dictatorial government of Saddam Hussein and ended the decades-long rule of the Baath Party. This created an opportunity for Iraq to establish new democratic, federal political institutions and reconstitute its security forces, but it also ushered in a period of chaos, violence, and political transition from which the country is still emerging. Latent tensions among Iraqis that were suppressed and manipulated under the Baath regime became amplified in the wake of its collapse. Political parties, ethnic groups, and religious communities competed with rivals and amongst themselves for influence in the post-2003 order, amid sectarian violence, insurgency, and terrorism. Misrule, foreign interference, and corruption also took a heavy toll on Iraqi society during this period, and continue to undermine public trust and social cohesion. In 2011, when the United States completed an agreed military withdrawal, Iraq's gains proved fragile. Security conditions deteriorated from 2012 through 2014, as the insurgent terrorists of the Islamic State organization (IS, aka ISIS/ISIL)—the successor to Al Qaeda-linked groups active during the post-2003 transition—drew strength from conflict in neighboring Syria and seized large areas of northern and western Iraq. Since 2014, war against the Islamic State has dominated events in Iraq, and many pressing social, economic, and governance challenges remain to be addressed. (See Table 1 below for basic data.) Iraqis are now celebrating the considerable successes their security forces and foreign partners have achieved in the fight against the Islamic State (see Figure 1 ), while warily eyeing a potentially fraught political path ahead. National legislative and governorate elections are planned for May 2018. Iraqi Prime Minister Haider al Abadi appears well positioned to campaign for reelection, although rivals from other Shia political factions may contest his leadership. Such potential challengers include former prime minister Nouri al Maliki and some figures associated with Iran-backed militia forces that are part of the Popular Mobilization Forces (PMF) mobilized to fight the Islamic State. Some Iraqi parties and individuals oppose a continued U.S military presence in Iraq and may scrutinize U.S.-Iraqi security cooperation during the election period. The Kurdistan Region of Iraq (KRI) maintains considerable administrative autonomy under Iraq's constitution, and held a controversial advisory referendum on independence from Iraq on September 25, 2017. From mid-2014 through October 2017, Kurdish forces controlled many areas that had been subject to territorial disputes with national authorities prior to the Islamic State's 2014 advance, including much of the oil-rich governorate of Kirkuk. However, in October 2017, Iraqi government forces moved to reassert security control in many of these areas, leading to some armed confrontations and casualties on both sides and setting back Kurdish aspirations for independence. Across Iraq, including in the KRI, long-standing popular demands for improved service delivery, security, and effective, honest governance remain widespread. Stabilization and reconstruction needs in areas liberated from the Islamic State are extensive. Paramilitary forces mobilized to fight IS terrorists have grown stronger and more numerous since the Islamic State's rapid advance in 2014, but have yet to be fully integrated into national security institutions. Iraqis are grappling with these political and security issues in an environment shaped by ethnic, religious, regional, and tribal identities, partisan and ideological differences, personal rivalries, economic disparities, and natural resource imbalances. Iraq's neighbors and other international powers are actively pursuing their diplomatic, economic, and security interests in the country. Iraq's strategic location, its potential, and its diverse population with ties to neighboring countries underlie its importance as an area of influence to U.S. policymakers. In general, U.S. engagement with Iraqis since 2011 has sought to reinforce Iraq's unifying tendencies and avoid divisive outcomes. At the same time, successive Administrations have sought to keep U.S. involvement and investment minimal relative to the 2003-2011 era, pursuing U.S. interests through partnership with various entities in Iraq and the development of those partners' capabilities—rather than through extensive deployment of U.S. military forces. The Trump Administration has sustained a cooperative relationship with the Iraqi government and has requested funding to continue security training for Iraqi forces beyond the completion of major military operations against the Islamic State. With those operations coming to a conclusion, the mission and nature of the U.S. military presence in Iraq is expected to evolve. U.S. officials and military personnel have discussed general plans to remain in Iraq at the invitation of the Iraqi government in order to assist Iraqis in consolidating gains made to date and to train security forces. The 115 th Congress has appropriated funds for ongoing U.S. military operations, in addition to security assistance, humanitarian relief, and foreign aid for Iraq. Congress is considering appropriations and authorization bills for FY2018 that would largely continue U.S. policies and programs on current terms. The goals, scope, and terms of some assistance are subject to debate and may evolve in relation to conditions in Iraq. In July 2017, Prime Minister Haider al Abadi visited Mosul to mark the completion of major combat operations there against Islamic State forces, which had taken the city in June 2014. Iraqi forces launched operations to retake Mosul in October 2016 and seized the eastern half of the city in January 2017. They then began operations in the city's more densely populated western half in February. Fighting in west Mosul resulted in greater displacement, casualties, and destruction of buildings and infrastructure than in the east, with some estimates of the city's overall reconstruction needs exceeding $1 billion. Estimates suggest thousands of civilians were killed or wounded during the battle, which displaced more than 1 million people. The defeat of IS forces in Mosul left the group with isolated areas of control in Tal Afar in Ninewa governorate, near Hawijah in Kirkuk and adjacent governorates, and in far western Anbar governorate (see Figure 2 , above). Iraqi forces have since retaken Tal Afar and Hawijah, and launched new Anbar operations in late October amid tensions elsewhere in the disputed territories between the Kurdistan Regional Government (KRG) and national authorities. Prime Minister Abadi visited the western border town of Al Qaim in November and raised the Iraqi flag, and in mid-November Iraqi officials announced they had retaken Rawa, the last large populated area held by IS fighters in Iraq. With IS control over distinct territories of Iraq now virtually ended, analysts expect IS leaders and fighters to shift toward insurgency tactics and avoid major confrontations in coming weeks and months. Experts warn that the group's resiliency and its ability to use such tactics effectively should not be underestimated. On June 7, 2017, Kurdistan Regional Government (KRG) President Masoud Barzani announced that the KRG would hold an official advisory referendum on independence from Iraq on September 25. Iraqi Prime Minister Abadi called the proposed referendum unconstitutional and requested that it be delayed or cancelled in favor of resolving KRG-Baghdad differences through dialogue. The United States government, other countries and international observers, and some of Iraq's neighbors adopted that same position. KRG President Barzani and other leading Kurds described the proposed referendum as an inherent right of the Kurdish people in pursuit of self-determination. Enthusiasm among some Kurds for the referendum reflected long-stated desires in an environment in which security and economic circumstances were more favorable than in the past because of post-2014 developments. However, KRG leaders said they intended to pursue separation negotiations with Baghdad after the referendum, raising the potential stakes of preexisting territorial and resource disputes and contributing to concern among Iraqi critics. In spite of U.S. and Iraqi opposition, Kurdish leaders held the referendum on time and as planned. According to Kurdish authorities, more than 72% of eligible voters participated and, of those votes deemed valid, roughly 92% were "Yes" votes and about 7% were "No" votes. In the wake of the referendum, Prime Minister Abadi has reiterated the national government's view that the referendum was "unconstitutional," and he and Iraq's national legislature and courts have called for its results to be "cancelled." Iraqi authorities also moved to begin reasserting national government control over all border crossings and the airspace of the KRI. Kurdish officials decried the measures, describing them as collective punishment and an attempt to institute a blockade. The September 25 referendum was held across the KRI and in other areas that were then under the control of Kurdish forces, including some areas subject to territorial disputes between the KRG and the national government, such as the multiethnic city of Kirkuk, adjacent oil-rich areas, and parts of Ninewa governorate populated by religious and ethnic minorities. Kurdish forces had secured many of these areas following the retreat of national government forces in the face of the Islamic State's rapid advance across northern Iraq in 2014. In October 2017, Prime Minister Abadi ordered Iraqi forces to return to the disputed territories that had been under the control of national forces prior to the Islamic State's advance, including Kirkuk. A handful of clashes resulted in some casualties on both sides, but Kurdish forces—to some extent divided among themselves over the wisdom of the referendum and relations with Baghdad—mostly withdrew without incident. The involvement of some Iran-backed Popular Mobilization Force militia units in Iraqi national forces' operations has fueled concerns about Iranian influence in Iraq, as have reports about attempts by Iranian officials to pressure Kurdish leaders over the disputed territories. Changes in territorial control in the disputed territories since October have upended the Kurds' financial and political prospects, and related disputes have fueled further division among Kurdish leaders and parties.