Iraqi conflict in the context of "Iraqi insurgency (2003–2011)"

A religious war or a war of religion, sometimes also known as a holy war (Latin: sanctum bellum), is a war and conflict which is primarily caused or justified by differences in religion and beliefs. In the modern period, there are frequent debates over the extent to which religious, economic, ethnic or other aspects of a conflict are predominant in a given war. The degree to which a war may be considered religious depends on many underlying questions, such as the definition of religion, the definition of 'war', and the applicability of religion to war as opposed to other possible factors.

According to scholars such as Jeffrey Burton Russell, conflicts may not be rooted strictly in religion and instead may be a cover for the underlying secular power, ethnic, social, political, and economic reasons for conflict. Other scholars have argued that what is termed "religious wars" is a largely "Western dichotomy" and a modern invention from the past few centuries, arguing that all wars that are classed as "religious" have secular (economic or political) ramifications. In several conflicts including the Israeli–Palestinian and Indo–Pakistani conflicts and the wars in Afghanistan, Syria and Iraq, religious elements are overtly present, but variously described as fundamentalism or religious extremism—depending upon the observer's sympathies. However, studies on these cases often conclude that ethnic animosities drive much of the conflicts.

The 1975 Algiers Agreement, also known as the Algiers Accord and the Algiers Declaration, was signed between Iran and Iraq to settle any outstanding territorial disputes along the Iran–Iraq border. Mediated by Algeria, it served as the basis for additional bilateral treaties signed on 13 June 1975 and 26 December 1975. The territorial disputes in question concerned Iraq's Shatt al-Arab and Iran's Khuzestan Province, and Iraq had wished to negotiate to end Iran's support for the then-ongoing Iraqi Kurdish rebellion after suffering a military defeat in the 1974–1975 Shatt al-Arab conflict. On 17 September 1980, shortly after the Iranian Revolution, the Iraqi government abrogated the treaty in light of another series of cross-border clashes between the two countries. On 22 September 1980, the treaty was completely voided with the Iraqi invasion of Iran, which triggered the eight-year-long Iran–Iraq War.

Since the 2003 invasion of Iraq, the detailed boundary delimitation of the treaty has remained de jure in force and binding under international law (per UNSC Resolution 619), though there is occasional friction between the two countries over the state of their border in the context of smuggling and the Iraqi conflict.

Throughout the 20th century, Iraq witnessed multiple periods of instability and conflict that prompted the creation and flight of many refugees. Earlier examples include the exodus of Iraqi Jews and the flight of Iraqi Kurds. The Iraqi invasion of Iran in 1980 and the ensuing Iran–Iraq War (1980–1988) triggered a deterioration of ties among the country's various ethnic and religious communities, and also exacerbated in violent events like the Ba'athist Arabization campaigns in northern Iraq (1968–2003), which led to the killing and displacement of thousands of minorities. The Iraqi invasion of Kuwait (1990) and the ensuing Gulf War (1990–1991), which ended with Iraq's defeat and the application of United Nations sanctions (1991–2003), also resulted in the creation of many Iraqi refugees. It was not until the beginning of the ongoing Iraqi conflict, however, that sustained waves of Iraqi refugees would be created, numbering in the millions: the 2003 invasion of Iraq and the ensuing Iraq War (2003–2011) killed and displaced hundreds of thousands of Iraqis, both internally and externally, and the later War in Iraq (2013–2017) forced even more people to flee from the country. Many Iraqi refugees established themselves in urban areas of other countries rather than in refugee camps.

In April 2007, there were approximately four million Iraqi refugees around the world, including: 1.9 million within Iraq; two million in neighbouring Arab countries, as well as in Iran and Turkey; and approximately 200,000 outside of the Middle East entirely. The United Nations High Commissioner for Refugees (UNHCR) has led the humanitarian efforts for Iraqi refugees. The number of displaced persons and refugees from the Iraqi conflict is considered to be the largest in the Middle East, though this figure may now be lower than that of the refugees of the Syrian civil war.