In 1868, Florida’s white elites faced a threat every bit as grave as the Civil War that had ended in Confederate defeat three years earlier. Congress had just forced Florida to rewrite its constitution to allow every man the right to vote. But adding thousands of newly eligible black residents to the rolls would abruptly make whites a voting minority.

The old guard’s only hope was to somehow ban black voters without violating Reconstruction acts passed by Congress after the Civil War. Huddled in Tallahassee backrooms throughout that cool January, they found just the ticket: a lifetime voting ban on anyone with a felony conviction. Combined with postwar laws that made it easy to saddle black residents with criminal records, legislators knew they could suppress black votes indefinitely.

Or at least for a century and a half. On Tuesday, Florida voted to end that 150-year-old ban by backing Amendment 4, which will return voting rights to more than 1 million Floridians who have already served out their sentences. The amendment garnered 64 percent of the vote.