By now it's a familiar and hackneyed war story. A jarring event rouses a dormant people. Diplomacy fails. Conflict erupts. The modern, mechanized nation overpowers the atavistic, feudal regime. The victors send soldiers, consultants, and contractors to free the oppressed, rebuild, secure vital resources and territory, and to put their stamp on the society that will emerge. In the midst of this benevolence, a loosely woven network of terror groups stages dogged acts of sabotage, kidnapping, assassination, and graphic murder that demoralize the occupiers. The victors are gradually forced to compromise those principles in whose name they first fought, or to withdraw. Sound like Iraq? It is. But it's also the United States of the Civil War.

Much like the September 2001 attacks on the World Trade Center, the April 1861 Confederate salvos at Fort Sumter forever changed the way Americans viewed their country. Like George W. Bush, President Abraham Lincoln dressed his military campaign in idealistic robes - as a noble crusade to free the slaves. Like Bush, Lincoln went to war without a viable plan for the aftermath.

"Mr. Lincoln gropes ... like a traveller in an unknown country without a map," wrote one New York World columnist in early 1865.

Georges Clemenceau, a French diplomat and journalist who would later serve two terms as his country's prime minister, observed that the US had "embarked on the abolitionist sea, without any clear idea of where their cause would lead."

As in Iraq, regime change left the South in social, economic, and political disarray. Slaves had made up nearly 40 percent of the population in the prewar South, and had provided its largely agrarian economy with a stable - and of course cost-effective - workforce. With emancipation, the nearly 3.5 million freedmen were - at least in theory - no longer tied to the land. Talks of enfranchisement for blacks were foreboding for Southern whites, conjuring visions of African-American majorities who could use the ballot to exact revenge on their former masters, or to further the programs of Republican activists and carpetbaggers from the North...