The ERA is a constitutional amendment that specifically states that women are entitled to the same legal rights as men. The amendment 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.”

In January 2020, Virginia became the 38th state to ratify the ERA since its introduction in 1972. With Virginia signing on, the ERA had finally achieved its ratification by two-thirds of all states required for its addition to the Constitution.

However, the ERA’s original deadline for ratification, established by Congress, was June 30, 1982. By 1977, it had only been ratified by 35 states. The three most recent states—Illinois, Nevada and Virginia—didn’t ratify it until 2017 onward.

In August 2020, the attorneys general of Illinois, Nevada and Virginia filed a lawsuit asking the court to allow the ERA to be added to the Constitution, despite missing its original deadline. The states claimed that National Archivist David Ferriero should have allowed it to be added to the Constitution after Virginia ratified it.

On Friday, U.S. District Judge Rudolph Contreras ruled against their request.

“Plaintiffs’ ratifications came after both the original and extended deadlines that Congress attached to the ERA, so the Archivist is not bound to record them as valid,” Contreras wrote in his 37-page ruling.

If the states appeal his ruling, the case could end up at the Supreme Court. It’s uncertain whether the nation’s highest court would accept the case or how the conservative-leaning court might rule on it.

Supporters of the ERA say that it is still necessary for the U.S. Constitution to have specific language affirming equal rights on the basis of sex.

Despite federal laws banning sex-based discrimination based, the pro-ERA website EqualRightsAmendment.org states that these laws can be differently interpreted in courts. As such, a lack of an explicit amendment leaves women to fight long, costly court battles to ensure they receive the same civil rights and legal protections given to men.

On January 22, Republican Alaska Senator Lisa Murkowski introduced a joint resolution with Democratic Maryland Senator Ben Cardin to remove the ERA’s ratification deadline.

In 2020, the U.S. House passed similar legislation to get rid of the approval deadline, but at the time, then-Republican Senate Majority Leader Mitch McConnell of Kentucky refused to let the Senate vote on it. When asked in February 2020 if he would support a Senate vote on it, McConnell told reporters: “Oh, I haven’t thought about that. I’m personally not a supporter, but I haven’t thought about it.”

However, even if the deadline removal is approved by both the House and Senate, legal questions remain about whether the states’ approvals, a majority of which occurred in the ’70s, would still count as binding over 40 years later.

In an email to Newsweek, Sue Waltisky, national communications director for Cardin, wrote that Article V of the Constitution, a section which covers the amendment ratification process, contains no time limits for the process.

“The states finally ratified the 27th Amendment in 1992 regarding congressional pay raises more than 200 years after Congress proposed it in 1789 as part of the Bill of Rights,” Waltisky wrote.

She added that the original deadline for ERA ratification wasn’t contained in the amendment itself but only in the text of the joint resolution proposing the amendment.

“This is to say the amendment itself has no arbitrary deadline attached,” she continued. “Congress can change the deadline it set.” She noted that Cardin’s and Murkowski’s resolution sought to do just that.

Furthermore, five state legislatures—Idaho, Kentucky, Nebraska, Tennessee and South Dakota—have voted to revoke their ERA ratifications since then, a legal move that may or may not be possible. If allowed, the ERA would then fall five states short of its needed 38-state threshold.

Newsweek contacted Virginia Attorney General Mark Herring for comment.

Update 3/6/2021, 3:26 p.m. ET: This article has been updated to include a statement from Senator Cardin’s national communications director, Sue Waltisky.