Pinned to the white lapels of some Democratic women in the audience at President Trump’s State of the Union on Tuesday night was a message: “ERA Yes.”

We’re ready in our suffragette white for tonight’s State of the Union. #WomenUnited pic.twitter.com/prl9Gz1Nqs — Rep. Debbie Dingell (@RepDebDingell) February 4, 2020

The buttons, worn by lawmakers including Reps. Alma Adams (D-NC) and Carolyn Maloney (D-NY), are an endorsement of the Equal Rights Amendment, which would enshrine gender equality into the US Constitution. Passed in 1972, the amendment needs to be ratified by 38 states to become law.

Thirty-five ratified the amendment quickly after passage, but then the movement stalled. However, in recent years, there’s been a renewed push to ratify the amendment, and in 2020, Virginia became the 38th state to do so.

There are still major hurdles to clear for the ERA to ever become American law. But on Tuesday, female lawmakers showed their support for a move advocates say would help people of all genders defend their rights in court, as well as sending an important message of gender equality across America.

The Equal Rights Amendment would prohibit gender discrimination

As it stands, the Constitution does not explicitly prohibit gender discrimination. The ERA would change that, adding a single line: “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 language is simple, but the process for approving it has been long and complex. After its passage by joint resolution of Congress, the amendment had until 1982 to be ratified by the required 38 states. The deadline passed, but as Sens. Lisa Murkowski (R-AK) and Ben Cardin (D-MD) wrote in a 2019 op-ed in the Washington Post, a renewed effort to ratify the amendment at the state level began about two years ago, and was buoyed in part by the Me Too movement.

Nevada ratified the amendment in 2017, and Illinois did the same in 2018, meaning only one more state was needed to get to 38. Virginia became that state in January. Virginia Del. Jennifer Carroll Foy, who sponsored the resolution to ratify the amendment, is attending the State of the Union tonight as Rep. Maloney’s guest.

“Democrats all across the country are fighting for women as we are here in the Capitol – for equal pay for equal work, against sexual harassment and assault, and for our equality to finally be enshrined in the Constitution,” Maloney said in a statement to media on Tuesday.

The ERA still has a long road ahead of it. In November, the House Judiciary Committee passed a resolution to eliminate the 1982 deadline. But President Trump’s Justice Department has said that Congress doesn’t have the authority to do that, and the National Archives and Records Administration, which has to certify the amendment, has said it will not do so.

Democratic attorneys general are now suing to force the certification of the amendment, and the issue is expected to make its way to the Supreme Court, the Associated Press reports.

If the ERA is ratified, advocates say it would give people more tools when they challenge discriminatory laws or practices in court. Federal courts have interpreted the Equal Protection Clause of the 14th Amendment as conferring some protection against sex discrimination, Emily Martin, vice president for education and workplace justice at the National Women’s Law Center, told Vox earlier this year. But adding an explicit ban on such discrimination in the Constitution would likely force courts to take the issue much more seriously.

People could use the Equal Rights Amendment to challenge anything from unequal pay to restrictions on abortion, Martin said. And it wouldn’t just affect women’s rights. By banning discrimination on the basis of sex, it could implicitly prohibit discrimination on the basis of sexual orientation and gender identity as well, offering protections to gay and trans people regardless of their gender.

The ERA would also have symbolic importance, Martin said: “It would, at the most fundamental level, recognize that gender equality is a foundational principle for the United States.”

Update: This story has been updated with new details about the ERA ratification process in 2020.