Washington (CNN) Three conservative-leaning states have filed a federal lawsuit in an attempt to stop the Equal Rights Amendment from being added to the US Constitution as it nears potential ratification .

The amendment, which would ban discrimination on the basis of sex and guarantee equality for women under the Constitution, needs three-fourths of US states -- 38 in total -- to be ratified after it was passed by Congress in the 1970s. Virginia, whose legislature will be all-Democratic in 2020, could be the 38th state to ratify it

Opponents have said the amendment isn't needed and would enable the removal of abortion restrictions, and the three states behind the lawsuit announced Wednesday -- Alabama, Louisiana and South Dakota -- argue that the deadline for ratification expired in 1982, when only 35 states had signed off. Five states, including South Dakota, that initially ratified the ERA have since rescinded their decisions, though two other states, Nevada in 2017 and Illinois in 2018, have recently ratified the ERA.

Advocates for the amendment have argued that the 1982 deadline is not binding and that rescinding a ratification has no legal validity. But the three states in Wednesday's lawsuit that are suing the archivist of the United States, David Ferriero, argue that he is "acting illegally" by continuing "to hold open the ratification process" and refusing to recognize some states' rescissions of the amendment.

"The people had seven years to consider the ERA, and they rejected it. To sneak it into the Constitution through this illegal process would undermine the very basis for our constitutional order," Alabama Attorney General Steve Marshall said in a statement.

He argued that while Alabama, Louisiana and South Dakota are "firmly committed to equality," the ERA "would not promote true equality, but rather a far-left agenda."

Marshall said state law versions of the ERA have been interpreted to "invalidate reasonable restrictions" on abortion or require that boys be allowed to compete in sports against girls. He argued that the amendment could threaten state-funded institutions that separate sexes, like women's shelters, prisons and colleges.

The National Archives and Records Administration said it has requested guidance from the Justice Department's Office of Legal Counsel.

"NARA does not intend to take any action regarding the ERA until, at a minimum, it receives the guidance it previously requested and in no event before February 15, 2020," it said in a statement Thursday.

The ERA Coalition, a group working for ratification of the ERA, called the lawsuit "a shameful effort to keep women from gaining Constitutional equality."

"Alabama has filed this lawsuit to thwart the democratic process, and the will of the overwhelming majority of Americans to enshrine the fundamental right to sex equality in our Constitution. The Attorney General of Alabama has done a disservice to women, including the women of Alabama," the organization said in a statement Wednesday.

In the US Congress, lawmakers in the House and in the Senate have sponsored legislation to remove the 1982 deadline.

Last month, the US House of Representatives' Judiciary Committee held a markup on a joint resolution that would eliminate the ratification deadline for the ERA. Companion legislation was also introduced in the GOP-controlled Senate.

Ratifying the ERA would be a "very important symbolic element to ensuring our Constitution recognizes that women are equal," Caroline Fredrickson, president of the American Constitution Society, a progressive legal organization, told CNN in an interview last year

More practically, Foy said, the amendment is essential for legal protections, in addition to the other nondiscrimination laws already in place, and would allow women more likely to prevail in legal cases of sexual assault and workplace harassment.

Meanwhile, there are other official protections that ensure equal treatment among the sexes. Many states have constitutional amendments or specifications that cover, among other statuses, discrimination based on sex. Some of these predate the ERA, and others, added after 1972, contain language similar to the ERA itself.