(WASHINGTON) -- Thousands of protesters gathered outside the Supreme Court of the United States on Wednesday as it hears arguments in the most serious legal challenge to Roe vs. Wade in 30 years, sparking passion on both sides of the heated abortion battle.
Hundreds more are expected in what's devovled into a dramatic scene of dueling rallies ahead of the most significant abortion rights case in decades.
The nation's highest court on Wednesday morning is considering a law from Mississippi that bans nearly all abortions after 15 weeks of pregnancy with no exceptions for rape or incest -- breaking the precedent set by Roe which doesn't allow states to prohibit the termination of pregnancies prior to fetal viability outside the womb at roughly 24 weeks.
Outside the court, two sides formed, separated by an invisible but deeply ideological barrier.
In the group for pro-abortion rights, where women told ABC News they travelled from all of the country -- including from Ohio, Pennsylvania, Virginia, New York and Rhode Island -- taking time off work to hoist signs reading, "abortion is healthcare," "grow abortion power," "defend women," "hands off my body'" and "equality begins in the womb. They repeatedly chanted in unison, "My body, my choice!"
Asked about the possibility of the justices crafting a middle ground, a woman from Washington told ABC News there is no such thing.
"These are our rights. They've been recognized for years. It's settled," she said.
Meanwhile, abortion opponents carried crosses, prayed the rosary and sang hymns. ABC News' Devin Dwyer reported the sense form many is that this is the consequential moment they've been praying God would deliver.
Ibah, a NICU nurse form Virginia, arrived after her shift with a coworker to show protest abortion.
"I just helped save a child born at 21 weeks," she said. "Life is precious."
Across the street, anti-abortion activists lined the sidewalk in the shadow of the U.S. Capitol holding dozens of oversized images of bloody aborted fetuses.
Speeches from both sides boomed over separate microphones, as each side fought to dominate.
Amber Gavin, 33, an independent abortion provider from Philadelphia who travels to North Carolina and Florida for her work, took the train to the nation's capital, instead, on Wednesday to show her support.
“Unfortunately, you know, we see a lot of anti-abortion protesters outside our clinic, harassing our staff and our patients. It's something that we deal with on a daily basis and it does make care, nobody should be forced to go through that as they're accessing basic health care,” Gavin told ABC News.
Kimberly McGuire, 36, executive director of Unite for Reproductive & Gender Equity, said she came to the court on behalf of young women and people of color living in the Midwest and the South who were unable to come and speak for their own constitutional right.
“There are people in every single state who are poised to fight back if this court decides the wrong way, who will be on the steps of their state legislatures, who will be speaking out and fighting to get this right back,” McGuire told ABC News.
The state of Mississippi, bringing its case to the high court after lower courts rejected it, argues Roe was wrongly decided and that each state should be allowed to set its own policy.
The Center for Reproductive Rights, a pro-abortion rights organization, which argues the decision to have an abortion should be left to a woman and her doctor, held a morning rally to kick off the historic day where women defended their constitutional right to an abortion and shared their own stories of having one.
“Having access to abortions made me a better parent because I was able to parent on my terms," said Kenya Martin, a pro-abortion rights activist outside the court.
A sea of abortion rights advocates huddled around a podium as movement leaders rallied the crowd's spirits.
“Abortion is not our dirty little secret. We did what’s best for us and that’s what matters," Martin added.
In the afternoon, abortion providers, clinic escorts, patients and other advocates are expected to engage in civil disobedience.
Shannon Brewer, director of Jackson Women’s Health, the last abortion provider in Mississippi and backbone of the case being heard this morning, made an argument for public health as well, reminding of the days before Roe when women died in resorting to so-called "back-alley" abortions.
"If you make abortion illegal, abortion does not stop," she said.
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 this month. Three in four Americans, including majorities of Republicans, independents and Democrats, say the decision of whether or not to have an abortion should be left to a woman and her doctor.
Separately, the Supreme Court has a still-pending decision in a separate dispute over Texas' unprecedented six-week abortion ban, SB8, which has denied women in Texas of the constitutional right to an abortion for nearly three months. Activists on Wednesday took aim at the Texas law, as well.
ABC News' Devin Dwyer contributed to this report.