In 1787, the men who wrote the Constitution added a provision for amendment—Article V—knowing that changing circumstances would demand revision. To amend meant, at the time, to correct, to repair, and to remedy; it especially implied moral progress, of the sort that you indicate when you say you’re making amends or mending your ways. The idea for an amendment clause, a constitutional fail-safe, came from the states, where people demanded that their constitutions be revisable, “to rectify the errors that will creep in through lapse of time, or alteration of situation,” as one town meeting put it. No single article of the Constitution is more important, the Framers believed, because, if you couldn’t revise a constitution, you’d have no way to change the government except by revolution.
Without Article V, the Constitution would not have been ratified. But, from the start, most amendments failed, and were meant to. Amending the Constitution requires a double supermajority: an amendment introduced in Congress has to pass both houses by a two-thirds vote, and then must be approved by the legislatures of three-quarters of the states. Also, a lot of proposed amendments are horrible. In March, 1861, weeks before shots were fired at Fort Sumter, Congress passed a doomed amendment intended to stop the secession of Southern states: “No amendment shall be made to the Constitution which will authorize or give to Congress the power to abolish or interfere, within any State, with the domestic institutions thereof, including that of persons held to labor or service by the laws of said State.” Others have been silly, like the amendment, proposed in 1893, that would have renamed the country the United States of the Earth. And plenty have been perfectly reasonable but turned out to be unnecessary. The Child Labor Amendment proposed to give Congress the “power to limit, regulate, and prohibit the labor of persons under eighteen years of age.” It passed Congress in 1924 and went to the states for ratification, where it failed; later, child labor was abolished under the terms of the Fair Labor Standards Act of 1938.
More than ten thousand amendments have been introduced into Congress. Many more never made it that far. Only twenty-seven have ever been ratified and become part of the Constitution. Looking at them all at once, straight off, you can see patterns. Most successful amendments involve a constitutional settlement in the aftermath of a political revolution. Ratifications have come, mostly, in flurries: first during the struggle over the Constitution itself, when its critics secured ratification of amendments one through ten, the Bill of Rights; then during the Civil War and Reconstruction, a second founding, marked by the ratification of amendments thirteen through fifteen; and, finally, during the Progressive Era, when reformers achieved amendments sixteen through nineteen. Scattered amendments have been ratified since, notably the Twenty-fifth, which established a procedure in the event of Presidential debility, and the Twenty-sixth, which lowered the voting age to eighteen. The Twenty-seventh Amendment, concerning congressional salaries, was ratified in 1992, but it was first proposed in 1789. All of these have been one-offs, rather than part of efforts to constitutionalize political revolutions.