Reconstruction, in U.S. history, the period (1865–77) that followed the American Civil War and during which attempts were made to redress the inequities of slavery and its political, social, and economic legacy and to solve the problems arising from the readmission to the Union of the 11 states that had seceded at or before the outbreak of war. Long portrayed by many historians as a time when vindictive Radical Republicans fastened black supremacy upon the defeated Confederacy, Reconstruction has since the late 20th century been viewed more sympathetically as a laudable experiment in interracial democracy. Reconstruction witnessed far-reaching changes in America’s political life. At the national level, new laws and constitutional amendments permanently altered the federal system and the definition of American citizenship. In the South, a politically mobilized black community joined with white allies to bring the Republican Party to power, and with it a redefinition of the responsibilities of government.