“. . . As Stevens pointed out, the reasoning that says that no states seceded because the Constitution won’t allow it would also say that no man can ever commit murder because the law forbids it. “Black Codes” were put in place in most Southern states that, through various means, some overt and some insidious (anti-vagrancy statutes were a particular favorite), limited the rights of blacks to work and to relocate. The legislative reconquest was backed by violence: the Ku Klux Klan, formed as a terrorist organization by ex-Confederate officers, began murdering and maiming assertive black citizens. In 1877, after a mere dozen years in which black suffrage and racial equality were at least grudgingly accepted national principles, the federal government pulled its last troops from the South and, in what could be called the Great Betrayal, an order of racial subjugation was restored. . .”

Source: How the South Won the Civil War | The New Yorker