Late last month, Illinois became the thirty-seventh state to ratify the Equal Rights Amendment, which would do what the Constitution currently does not: guarantee that women are equal to men. The ratification by the state’s House of Representatives, by a 72-45 vote, had symbolic resonance because Illinois was the home of Phyllis Schlafly, an anti-feminist activist who led a national campaign against in the ERA in the 1970s. But the vote was largely symbolic for another reason: It came 36 years too late.

A constitutional amendment, once it has been approved by two-thirds of the U.S. House and Senate, must be ratified by three-fourths of the states to become law—which, since Hawaii entered the union in 1959, amounts to 38 states. Alas, the ERA is not just one state short of passage because the deadline for state ratification was way back on June 30, 1982, by which time only 35 states had ratified it.

But the ERA isn’t just a relic of second-wave feminism. It’s still necessary today, as equality for women in the United States is not enshrined in the Constitution; it is merely a matter of legal interpretation. Some believe that the amendment may yet become law if a thirty-eighth state ratifies—the expired deadline notwithstanding.

The ERA, first introduced by suffragist Alice Paul in 1923, originally posited that “men and women shall have equal rights throughout the United States and every place subject to its jurisdiction.” The amendment was reintroduced to Congress each year after that, until it passed in 1972. By that time, it had been rewritten to say, “Equality of rights under the law shall not be denied or abridged by the United States or by any state on account of sex.”

A slew of states were quick to ratify the amendment after it passed Congress in 1972, but the pace slowed down as right-wing groups mounted opposition campaigns. The ERA’s opponents argued that the amendment would be harmful to women, increase abortion rights, and open the door to same-sex marriage. The amendment initially faced a 1979 ratification deadline, which Congress later extended to 1982; only 35 states had ratified the ERA before the new deadline was up.