Less than a decade later, however, former slaves and freeborn blacks helped choose delegates to state constitutional conventions across the South, including the one in Charleston. These groundbreaking 1867 and 1868 elections, which followed a congressional mandate, gave birth to real, if short-lived, interracial democracy. African Americans occupied one-quarter of the seats in the conventions as a whole and a majority of them in Louisiana and South Carolina.

The conventions drafted constitutions reflecting the progressive priorities of their mostly Republican delegates, whose party represented the left wing of American politics, particularly on race. Whereas postbellum Democrats campaigned on racist platforms, most Republicans were committed to using government to secure black rights.

All of the new constitutions guaranteed black men the right to vote, a feature that for a time reshaped the American body politic. As late as 1866, less than 1 percent of African American men in the United States had been eligible to vote, and not one of them lived south of the Mason-Dixon Line. Up north and out west, white citizens had shown little interest in expanding voting rights, rejecting colorblind suffrage initiatives in Connecticut, Ohio, and Kansas in 1867. Yet by the following year, hundreds of thousands of black men were voting in national, state, and local elections held in the seven ex-Confederate states that had by then ratified their constitutions—all before the 15th Amendment enfranchised black men throughout the country in 1870.

The Reconstruction constitutions also protected black civil rights, unlike those of most Northern states. They outlawed inhumane and undemocratic provisions from the antebellum era, including corporal punishment for crime and property-owning qualifications for jury service. The conventions in Georgia and the Carolinas expanded the property rights of married women, black and white.

No convention was as revolutionary as South Carolina’s, if only because no state had so reactionary a political culture or so outdated a constitution. Christened the “Congo Convention” by opponents, the black-majority assembly abolished debtors’ prison and property-owning qualifications for serving in the state legislature. It provided for the popular election of the governor and the state’s presidential electors. And delegates also paved the way for the legalization of divorce for the first time in South Carolina history.

By enfranchising black men, the new state constitutions laid the groundwork for Republicans to assume power throughout the South by the early 1870s. African Americans made up a majority of the electorate in three Southern states and a sizeable proportion in the rest. Aided by the Union League, a grassroots coalition of Republican clubs that promoted voter registration, black turnout often approached 90 percent during Reconstruction.