The 2003 war changed Iraq forever because of the failure of the USA and its allies to provide stability and security for the people of Iraq, with the resulting separation of the major population groups within Iraq and the extrusion of minorities. Usually as a scapegoat for their own failings or as distractions to larger ambitions, regimes get rid of unwanted populations by extermination (genocide) or by ethnic cleansing. Societies, when they are insecure and feel threatened and in the absence of a strong governing authority, will do the same. If a population can move to another part of a state where they feel safe because they cohabit there in safety with members of their own ethnic or religious group, they become internally displaced. Minorities who lack any such safe haven in a polity try to cross a border if at all possible and become refugees. However, if an oppressed group cannot cross a border, forced migration easily leads to attempts at extinction.

The Iraqi refugee exodus has been examined at four-year intervals, beginning in 2002 before the onset of the Iraq War, then in 2006 before the upsurge in Sunni–Shiite violence that lasted until 2008. The 2010 examination took place after the separation of most Sunnis and Shiites and the flight of minority populations but before both the March 2010 Iraq elections and the outbreak of the Syrian civil war in 2011. In the final cross-sectional view in 2014, Iraqi refugees were expected to have returned; few did. In each temporal cross-section, specific groups become the focus – Kurds in 2002–3, Turkmens, Assyrian and Armenian Christians and Palestinians in 2006, smaller minorities in 2010, and refugees returning from Syria in 2014. These cross-sectional historical and ethno-religious slices dealing with internally displaced peoples (IDPs) and refugees over twelve years depict the dimensions and character of the Iraqi refugee problem and its legacy in Iraq. They also demonstrate that the war has changed the human geography of Iraq, probably for decades to come, as a direct result of the failure of the USA and its allies to provide a stable and secure environment for its people. Iraq was left with its small minorities largely extruded and its larger groups – Kurds, Sunni Arabs and Shia Arabs – mostly resettled within their own virtually homogeneous enclaves.