Demonstrators gathered in Washington on Friday for the country's largest annual anti-abortion rally around the anniversary of the landmark 1973 Supreme Court decision establishing the right to an abortion -- but this year, 49 years later, they march with the fate of Roe v. Wade more uncertain than ever.
"March for Life" organizers expressed optimism that the court's 6-3 conservative majority, appearing sympathetic to their side, is headed toward altering almost 50 years of precedent since the original decision protecting a woman's right to end a pregnancy with limited state regulation.
MORE: Roe v. Wade on the line as Supreme Court takes up Mississippi abortion rights case
"We expect this year's March for Life to be historic with even higher levels of enthusiasm from participants," Jeanne Mancini, president of March for Life, told ABC News in a statement. "We are all hopeful that, with the Dobbs v. Jackson Women's Health Organization case before the Supreme Court, this year will bring us much closer to building the culture of life we have all marched for since Roe v. Wade was imposed on our nation nearly 50 years ago."
Leah Millis/Reuters
Anti-abortion activists attend the annual "March for Life", in Washington, D.C., Jan. 21, 2022.
Friday's rally -- under the theme "equality begins in the womb" -- began at noon on the National Mall with a concert and remarks from speakers, culminating in a march to the Supreme Court building. Scores of demonstrators, many in high school and traveling from out of state, carried signs and called out chants while marching through the nation's capital, appearing emboldened that the court finally took up a challenge this term to the long-standing precedent.
To that end, former Vice President Mike Pence, who has repeatedly called for reversing Roe, is scheduled to address the National Pro-Life Summit in Washington on Saturday to "prepare for a post-Roe America," according to organizers.
MORE: 2021 was pivotal year for abortion laws in America
The events come less than two months after the high court heard Dobbs v. Jackson Women's Health Organization, a case on the constitutionality of a Mississippi abortion ban after 15 weeks – which has no exceptions for rape on incest. The court is expected to hand down its decision in June, just months before the midterm elections.
Leah Millis/Reuters
Anti-abortion activists attend the annual "March for Life", in Washington, D.C., Jan. 21, 2022.
If the high court overturns Roe, the battle over abortion would likely shift to state legislatures. So far, a dozen states have so-called trigger laws set to ban all or nearly all abortions the moment the Supreme Court delivers a favorable decision. At least ten more have similar laws that could quickly follow suit.
And in the last year alone, a record number of states have enacted more than 100 stringent new restrictions on abortion access, according to the Guttmacher Institute, an abortion rights research organization.
MORE: Supreme Court deals another blow to Texas abortion providers that want new law blocked
Susan Walsh/AP
People attend the March for Life rally on the National Mall in Washington, D.C., Jan. 21, 2022.
In a signal of how the justices may rule on the Mississippi case, the court just handed a win to anti-abortion advocates on Thursday by thwarting an attempt by abortion providers to block Texas' restrictive six-week abortion ban, SB8, which has denied women in Texas of the constitutional right to abortion since September.
MORE: Some states move to protect abortion rights in face of challenge at Supreme Court
Justice Sonia Sotomayor, in a separate blistering dissent from the majority, wrote: "This case is a disaster for the rule of law and a grave disservice to women in Texas, who have a right to control their own bodies. I will not stand by silently as a State continues to nullify this constitutional guarantee."
Majorities of Americans support the Supreme Court upholding Roe v. Wade and oppose states making it harder for abortion clinics to operate, according to an ABC News/Washington Post poll from November. Three in four Americans, including majorities of Republicans, independents and Democrats, say the decision of whether to have an abortion should be left to a woman and her doctor.
J. Scott Applewhite/AP, FILE
The Supreme Court is seen at dusk in Washington, Oct. 22, 2021.
White House press secretary Jen Psaki addressed the anniversary of the landmark decision at Friday's White House briefing.
"Reproductive health care has been under extreme and relentless assault ever since, especially in recent months," she said. "We're deeply committed to making sure everyone has access to care and we will defend it with every tool we have. That includes continuing to work with Congress to pass the Women's Health Protection Act and codify this fundamental right into law."
Friday's march is planned each year on or around the anniversary of the Roe v. Wade decision, handed down 49 years ago on Jan. 22, 1973.
ABC News' Devin Dwyer and Brittany Shepherd contributed to this report.