Of all the things that Virginia may pass now that Democrats have won control of the state legislature, none have been so long in the making as the Equal Rights Amendment.

First proposed almost a century ago and passed by Congress in 1972, the constitutional amendment — whose main clause reads, “Equality of rights under the law shall not be denied or abridged by the United States or by any State on account of sex” — has sweeping implications.

For women, it would bolster pay equity, domestic violence laws and pregnancy discrimination protections, among many other things. It could also affect men, such as by guaranteeing paid paternity leave equal to maternity leave.

The amendment was ratified by only 35 of the necessary 38 states before a 1982 deadline. Nearly four decades later, in 2017, Nevada became the 36th. In 2018, Illinois was the 37th. Now, Virginia’s incoming Democratic leaders have promised to take it up immediately when the legislature convenes in January — and given that it failed in the Virginia Senate by only one vote when the body was under Republican control, passage is almost assured.

“If we get it to the floor and let people vote, then it will become law,” said Gov. Ralph Northam, a Democrat. “Virginia will be next in line to pass the ERA.”

Advocates, almost giddy in interviews, said ratification seemed more likely than it had at any point in the past 40 years.

“It was so exhilarating,” Carol Jenkins, co-president and chief executive of the ERA Coalition, said of watching the election results come in. “This was first introduced in 1923, so almost a century of someone working to get equality for girls and women in this country, and this is as close as we’ve ever gotten.”

The big question is whether Congress will void the ratification deadline — or whether it was ever enforceable to begin with.

How did we get here?

The history of the Equal Rights Amendment is long and complicated.

Suffragist Alice Paul wrote the first version and got it introduced in Congress in 1923 — meaning that when Congress gave its approval in 1972, it was a breakthrough already 50 years in the making. Thirty-five states ratified the amendment within five years of its passage.

But anti-feminist leader Phyllis Schlafly mobilized a quick and extraordinarily successful movement to stop the ERA, warning of disastrous consequences if traditional gender roles were eroded. Among other things, she argued that the amendment would force women to serve in combat and render single-sex bathrooms obsolete.

Congress extended the ratification deadline from 1979 to 1982, but no additional states signed on. (Three-fourths of the states — 38 out of 50 — must ratify an amendment to add it to the Constitution.)

For nearly four decades, it seemed that was the end of it. But in 2017, Nevada, which had rejected the amendment in 1977, brought it back from the dead. Illinois followed.

Rep. Carolyn Maloney of New York, who has been pushing for ratification since she came to Congress in 1993, said President Donald Trump’s election and the #MeToo movement had reignited the effort. Democratic victories also contributed: Nevada ratified the amendment the year after its legislature went blue, and if Virginia follows, it will be for the same reason.

What about the deadline?

It could be repealed, or challenged in court, or both.

Constitutional amendments don’t normally have ratification deadlines; in fact, the 27th Amendment was ratified in 1992, more than two centuries after Congress passed it. And supporters argue that the Equal Rights Amendment deadline is unenforceable because it is stated only in the preamble to the amendment, not in the amendment itself.

“It’s been extended by Congress, so if you can extend it, you can certainly strike it,” said Rep. Jackie Speier of California, the lead sponsor of a bipartisan House resolution to repeal the deadline.

But whether or not the deadline is legitimate, there is a good chance Congress will get rid of it.

The Democratic-led House held a hearing in April on the resolution, which has 215 cosponsors. The next step is a House Judiciary Committee markup, which Speier said would happen in the next two weeks. She said a full House vote was likely before the end of the year.

What the Republican-led Senate will do is less certain. Sen. Benjamin Cardin, D-Md., who is the primary sponsor of the Senate resolution, said he believed the measure — currently before the Judiciary Committee — had enough votes to pass if brought to the floor. Two Republicans, Sens. Lisa Murkowski of Alaska and Susan Collins of Maine, are cosponsoring it.

What happens next?

Legal experts disagree on whether Congress has the authority to remove the deadline — or, if it does, whether its removal can apply retro­actively. In other words, if Virginia ratifies the ERA before Congress passes the deadline legislation, does it count?

Supporters note that Article V of the Constitution, which lays out the process for amendments, does not say ratification must happen within a certain period of time.

Another source of confusion is that legislators in five states — Idaho, Kentucky, Nebraska, South Dakota and Tennessee — have voted to rescind their ratifications.

Based on legal precedent, that doesn’t matter; some states also tried to rescind their ratifications of the 14th and 15th Amendments, and their original ratifications were counted anyway. But opponents could try to challenge the amendment on that basis.

“We fully anticipate that there will be a Supreme Court decision involved in this,” said Krista Niles, outreach and civic engagement director at the Alice Paul Institute, one of the main organizations promoting the ERA.