Three amendments ratified between 1865 and 1870 remade the Constitution after the Civil War. The Thirteenth abolished slavery. The Fourteenth made anyone born or naturalized in the United States a citizen owed due process and equal protection. The Fifteenth barred denying the vote by race. Together they reversed the original Constitution's logic, turning the federal government into the guarantor of rights against the states. Almost immediately the Supreme Court read them narrowly and Southern states defied them openly, leaving the promises dormant for nearly a century — until the civil rights movement forced what scholars call a second founding.
In five years, between 1865 and 1870, the United States rewrote its own founding document three times. The Thirteenth Amendment ended slavery. The Fourteenth made nearly everyone born on American soil — all under its jurisdiction — a citizen, owed due process and the equal protection of the laws. The Fifteenth said the vote could not be denied because of race. For the first time the Constitution promised equality, and it aimed that promise at the states where people actually lived. Scholars now call this the second founding. Yet within a generation the Supreme Court had hollowed the words out and Southern states defied them in the open. The promise sat in the Constitution, near-dead, for almost a hundred years before the civil rights movement forced the nation to honor it. These three amendments are the legal engine of many of the great freedom struggles since.