Reconstruction was the period in American history immediately following the Civil War during which the South was, at least in theory, put back together. Reconstruction initially referred to the political process in which the seceded states were readmitted to the Union; this aspect was completed in 1877. Reconstruction also had a social context which lasted much longer and mixed the contending forces of blacks and whites, and federal and local governments.Not surprisingly the war had created two different nations; the social and economic conditions of North and South were vastly different in 1865. Even before the war had ended, various Reconstruction Plans were advanced. As soon as peace was achieved, the Radical Republicans in Congress imposed Republican governments on the seceded states; these unpopular state and local regimes depended upon black votes to survive. Political tensions were intense on the national level and eventually resulted in the Impeachment of Andrew Johnson. The Election of 1868 brought U.S. Grant, the Union war hero, to the presidency; his terms in office marked the beginning of a Republican ascendancy in American politics.