How is the Constitution amended?

Article V lays out the only two ways to amend the Constitution, and both have a propose stage and a ratify stage. Proposal: either two-thirds of both the House and Senate vote to propose an amendment, or two-thirds of state legislatures apply for a national convention to propose one. Ratification: three-fourths of the states must then approve it, either through their state legislatures or through state ratifying conventions — Congress picks which method. Every one of the 27 amendments actually added to the Constitution has gone the congressional-proposal route; the convention-for-proposing-amendments path has never been used, despite periodic pushes to trigger one. Ratification by convention was used exactly once, for the 21st Amendment repealing Prohibition in 1933 — every other amendment was ratified by state legislatures. Article V also contains two built-in protections: it barred any amendment before 1808 from touching the slave-trade and capitation-tax clauses, a compromise now moot, and it permanently guarantees that no state can be deprived of equal representation in the Senate without its own consent — the one part of the Constitution that, as written, cannot be amended away without a state’s agreement. The deliberate difficulty is the design: the framers wanted amendment possible but hard, so the document could evolve without being rewritten by momentary majorities.