History
Why Constitutional Amendments Require Supermajorities
Quick fact
In the United States, a constitutional amendment requires a two-thirds vote in both houses of Congress and ratification by three-fourths of states—a supermajority bar far higher than the simple majority used for ordinary legislation.
Why this is interesting
You know that to pass a law, you usually need just 50% plus one vote. But to change the Constitution, you need far more. Why the difference?