Whether the Constitution has actually been amended for the 28th time—and for the first time in more than a quarter century—is now officially in question and a matter for the courts to decide. Even before the two Democratic-led chambers of the Virginia legislature voted today, supporters and opponents of the ERA had filed dueling federal lawsuits, launching a legal battle that could wind up in the Supreme Court.

A deadline that Congress originally imposed (and later revised) for ratification of the amendment by the states has long since passed. ERA backers are trying to get the deadline invalidated, while foes want not only to keep the lapsed due date intact but to prevent Congress from retroactively eliminating it.

As a generation of American schoolchildren learned from Schoolhouse Rock, a bill becomes a law when the president signs it (or Congress overrides his veto). But the endpoint for affixing an amendment to the Constitution is a bit murkier. Congress, through a two-thirds majority vote in each chamber, proposes changes, and then three-quarters of the state legislatures must ratify them. But then what happens?