Abortion rights advocates geared up to mobilize in the nation’s capital and across the United States on Tuesday following the leak of a draft decision signaling that the Supreme Court’s right-wing majority is poised to overturn Roe v. Wade.

“People should take to the streets across the country.”

While the decision outlined in the draft opinion—authored by Justice Samuel Alito—is not yet final, it would strike a devastating blow to reproductive rights in large swaths of the U.S. Experts at the Guttmacher Institute have estimated that if the landmark 1973 decision is overturned, 26 states are “certain or likely” to completely outlaw abortion.

At least 13 states—including Arkansas, Kentucky, Utah, and Louisiana—currently have in place so-called “trigger laws” that would ban abortion in all or most cases automatically if the Supreme Court ends Roe.

The high court’s final ruling in the closely watched case, which is centered on an abortion ban in Mississippi, is expected within the next two months.

“We’re mobilizing,” Shaunna Thomas, co-founder of UltraViolet, tweeted in the wake of Politico‘s report on the draft, which set off widespread outrage and spurred flash protests outside the Supreme Court Monday night.

“Be at SCOTUS or any federal courthouse tomorrow at 5 pm,” Thomas wrote late Monday. “The leaked draft decision overturning Roe has confirmed everything we knew about this court’s intentions and it is giving us an opportunity to show them how ungovernable we will be if they follow through.”

An end to Roe is an outcome that right-wing forces in the U.S., backed by corporate power and cash, have been working toward for decades—and they appear prepared to take full advantage should the high court ultimately rule in their favor.

Citing a person familiar with the court’s deliberations, Politico revealed that “four of the other Republican-appointed justices—Clarence Thomas, Neil Gorsuch, Brett Kavanaugh, and Amy Coney Barrett—had voted with Alito in the conference held among the justices after hearing oral arguments in December, and that line-up remains unchanged as of this week.”

Hours before Alito’s draft opinion was made public, the Washington Post reported that “leading anti-abortion groups and their allies in Congress have been meeting behind the scenes to plan a national strategy that would kick in if the Supreme Court rolls back abortion rights this summer, including a push for a strict nationwide ban on the procedure if Republicans retake power in Washington.”

“The effort, activists say, is designed to bring a fight that has been playing out largely in the courts and state legislatures to the national political stage—rallying conservatives around the issue in the midterms and pressuring potential 2024 GOP presidential candidates to take a stand,” the Post noted.

Democratic attempts to enshrine Roe into federal law, meanwhile, have foundered as Senate Republicans and Sen. Joe Manchin (D-W.Va.) remain opposed to legislation that would do so. In late April, Manchin joined the unified GOP in filibustering the House-passed Women’s Health Protection Act (WHPA), refusing to even allow a vote on the measure itself.

“As one of the 1 in 4 women in this country who have chosen to have an abortion, I am outraged and disgusted by the reported draft SCOTUS opinion,” Rep. Pramila Jayapal (D-Wash.), chair of the Congressional Progressive Caucus, said late Monday.

“People should take to the streets across the country,” Jayapal added. “Right now, the Senate can pass an exception to the filibuster and codify Roe v. Wade. This is the most dramatic setback for women’s rights in decades.”

Nancy Northup, president and CEO of the Center for Reproductive Rights, echoed that warning in a statement.

“If the Supreme Court overturns Roe v. Wade, it will be an unjustified, unprecedented stripping away of a guaranteed right that has been in place for nearly five decades,” said Northrup. “It would represent the most damaging setback to the rights of women in the history of our country.”