The next thing Republicans in Congress did was to write the Fourteenth Amendment . It was a powerful amendment meant to change the Constitution as it was. It said: "No State shall deprive any person of life, liberty or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws ."
It says that the states must provide equal protection of the law to all their citizens. But suppose they don't? The South had fought for states' rights. Many Southerners thought each state should be free to make its own decisions. If a state wanted an aristocratic society with layers of privilege and unfairnesswell, if that was what the majority of its people wanted, why shouldn't they have it? This was what one famous judgeOliver Wendell Holmes had to say about that: "The history of most countries has been that of majoritiesmounted majorities, clad in iron, armed with deathtreading down the tenfold more numerous minorities."
The Constitution makers had realized that majorities are sometimes tyrannical. The Bill of Rights was meant to protect minorities from abuses by the majority. But it only covered federal laws. The Fourteenth Amendment protected citizens from tyranny by the states. If states pass unfair laws then Congress can override them. That's what the Fourteenth Amendment said. It took power from the states and gave power to the federal government. Andrew Johnson didn't like it a bit.