WASHINGTON (CN) – Attorneys general from three Democrat-led states filed a federal lawsuit Thursday seeking to force the U.S. archivist to add the Equal Rights Amendment to the Constitution after Virginia became the 38th state to ratify it this week.

“For too long, women have not been afforded the same protections as men under the Constitution,” Virginia Attorney General Mark Herring, a Democrat, said in a statement announcing the lawsuit. “Our history is full of strong, amazing women, who faced countless barriers in order to accomplish their dreams and goals. Without their perseverance and tireless hard work we would not be in the position we are today.”

Nearly 100 years in the making, the constitutional amendment would guarantee equal rights for women by outlawing sex discrimination. It was first introduced in 1923 and passed by Congress in 1972, and was then sent to state legislatures for ratification.

Democratic attorneys general from Illinois and Nevada joined Virginia in the lawsuit. Nevada ratified the ERA in 2017, followed by Illinois the next year. On Monday, Virginia became the crucial 38th state to approve it. Constitutional amendments require the approval of three-fourths of the states, or 38 of 50.

In Thursday’s 18-page complaint, the attorneys general pointed to the amendment process laid out in Article V of the U.S. Constitution.

“The amendment process generated significant debate among the framers and was carefully designed to balance the need for stability in our governing document with flexibility to adapt that document as needed,” the lawsuit states, citing James Madison’s opinion that the amendment process “guards equally against that extreme facility, which would render the Constitution too mutable; and that extreme difficulty, which might perpetuate its discovered faults.”

The complaint continues, “Under Article V, a proposed constitutional amendment automatically becomes ‘valid to all Intents and Purposes … as soon as it is ‘ratified by the legislatures of three fourths of the several states.’ For that reason, the Equal Rights Amendment became part of the U.S. Constitution immediately upon Virginia’s ratification.”

But some, including the Trump administration’s Justice Department, have said the ERA is not the law of the land yet.

In an opinion released earlier this month, Assistant U.S. Attorney General Steven A. Engel said the extended timetable of ratification is contrary to the intent when the founders designed the system to amend the U.S. Constitution.

Hawaii became the first state to ratify the ERA in 1972. Many states followed, with Indiana becoming the 35th state to approve it in 1977. However, the process then stalled when conservative groups pushed back with concerns about how the amendment would impact abortion and the gender equality movement.

Virginia’s approval this week pushed the amendment over the 38-state threshold more than four decades after its first state ratification.

“The only constitutional path for amendment would be for two-thirds of both houses (or a convention sought by two-thirds of the state legislatures) to propose the amendment once more and restart the ratification process among the states,” Engle wrote in the opinion. (Parentheses in original.)

A number of Republican state attorneys general have also filed suit to preemptively block ratification, claiming the deadline has expired.

The ERA is made up of three simple sections. The first states, “Equality of rights under the law shall not be denied or abridged by the United States or by any State on account of sex.”

The final two sections state, “The Congress shall have the power to enforce, by appropriate legislation, the provisions of this article,” and “This amendment shall take effect two years after the date of ratification.”

“Although potential legal hurdles remain, an amendment to the U.S. Constitution would provide the ultimate foundational protection for women under the law,” said former federal prosecutor and legal analyst Todd Stone.

He said the ERA would increase the level of scrutiny the U.S. Supreme Court would apply when considering equal protection cases based on gender.

“Those issues would become subject to the Supreme Court’s highest level of scrutiny; whereas the Court currently applies an intermediate scrutiny standard when balancing laws that have a disproportionate impact on women as a class,” Stone said.

Advocates of the amendment remain hopeful. Carol Jenkins, co-president and CEO of the ERA Coalition and Fund for Women’s Equality, said in a statement that a recent poll by her organization found 94% of Americans want to see it added to the Constitution.

“This country is ready for constitutional equality for women,” she said. “This movement cannot be stopped. We need the Equal Rights Amendment in the Constitution.”