THE surrender of Confederate Gen. Robert E. Lee at Appomattox Court House, 150 years ago next month, effectively ended the Civil War. Preoccupied with the challenges of our own time, Americans will probably devote little attention to the sesquicentennial of Reconstruction, the turbulent era that followed the conflict. This is unfortunate, for if any historical period deserves the label “relevant,” it is Reconstruction.

Issues that agitate American politics today — access to citizenship and voting rights, the relative powers of the national and state governments, the relationship between political and economic democracy, the proper response to terrorism — all of these are Reconstruction questions. But that era has long been misunderstood.

Reconstruction refers to the period, generally dated from 1865 to 1877, during which the nation’s laws and Constitution were rewritten to guarantee the basic rights of the former slaves, and biracial governments came to power throughout the defeated Confederacy. For decades, these years were widely seen as the nadir in the saga of American democracy. According to this view, Radical Republicans in Congress, bent on punishing defeated Confederates, established corrupt Southern governments presided over by carpetbaggers (unscrupulous Northerners who ventured south to reap the spoils of office), scalawags (Southern whites who supported the new regimes) and freed African-Americans, unfit to exercise democratic rights. The heroes of the story were the self-styled Redeemers, who restored white supremacy to the South.

This portrait, which received scholarly expression in the early-20th-century works of William A. Dunning and his students at Columbia University, was popularized by the 1915 film “Birth of A Nation” and by Claude Bowers’s 1929 best-selling history, “The Tragic Era.” It provided an intellectual foundation for the system of segregation and black disenfranchisement that followed Reconstruction. Any effort to restore the rights of Southern blacks, it implied, would lead to a repeat of the alleged horrors of Reconstruction.