AP Photo

Insurgencies and civil wars often gain attention in the United States only when waves of violence batter urban frontlines abroad. But once the combat ends and the cameras go home, interest here swiftly recedes. Yet, the lingering effects of the fighting—particularly on human capital—have profound strategic implications for the stability, democracy and prosperity of a state emerging from war.

A case in point is Iraq, a country that has experienced three major wars over the past three decades: the Iran-Iraq war (1980–1988), the Gulf War (1990–1991) and the Iraq War (2003–2011). Each conflict not only devastated the country's economy and infrastructure but also triggered waves of emigration and internal displacement. According to the United Nations High...