RICHMOND, Va. -- Since she was just 12 years old, Stephanie Stone has marched through streets in cities across America demanding an end to abortion and the beginning of a "post-Roe generation." Soon, it could be inaugurated on her watch thanks to years of relentless advocacy -- and a stroke of luck.
"It's exciting. Also, a little bit scary," said Stone, 26, a Pennsylvania native, a Catholic University graduate and organizer with Students for Life ahead of the Supreme Court's decision on the future of Roe v. Wade.
"There's a lot of tension right now," Stone said, "which is why I think it's important that we don't just shirk back and say, oh, it'll be taken care of, but rather that we're the ones on the front lines."
With the court soon expected to roll back nearly five decades of abortion rights precedent, Stone and other leaders of the anti-abortion movement are preparing to take their fight to individual statehouses backed by a highly-coordinated and well-funded strategy years in the making.
WATCH: Inside the "Post-Roe Generation"
"We obviously would want to abolish abortion and protect life from the moment of conception, but we're going to work in each state to do that in different ways," Stone said.
A leaked draft Supreme Court opinion last month showed the conservative majority of justices ready to overturn Roe entirely, clearing the way for each state to set its own policy on abortion and fulfilling opponents' long-sought demand.
"All the reasoning, all the thoughts that we've had over all the years are here on paper; all the things that we've worked for, for almost 50 years," said Marjorie Dannenfelser of the draft written by Justice Samuel Alito. Dannenfelser is president of Susan B. Anthony Pro-Life America, the powerful political arm of the anti-abortion movement.
On the cusp of a major victory at the court, ABC News Live interviewed dozens of grassroots volunteers and top movement leaders about the significance of this potential turning point on abortion rights and how it came to pass.
"Abortion is the human rights violation of our generation, of our lifetime. The biggest human rights abuse we're ever gonna see," said Lauren Marlowe, 18, a member of Students for Life, who joined a rally of several thousand anti-abortion advocates in Richmond this spring.
Advocates credit Marches for Life, which have been held in cities nationwide and in the nation's capital each January since 1974, with maintaining momentum for a popular opposition to abortion rights.
"Years ago, the other side, so to speak -- pro-abortion advocates -- thought that we would become desensitized to abortion, but nothing could be further from the truth," said Jeanne Mancini, president of March for Life Education and Defense Fund. "Our marches have grown and our movement's just gotten stronger."
The movement has also benefited from a singular drive in political campaigns: electing lawmakers who oppose abortion and pledge to vote to end it.
"The people that sit on the [Supreme] Court now are the fruit of of their own good work, but they're also culmination of our own strategy, which was to elect senators that would confirm good judges that good presidents have nominated," said Dannenfelser, whose organization has worked to recruit, fund and elect anti-abortion candidates since 1992.
Dannenfelser founded Susan B. Anthony List, named after the historic champion of women's rights who also opposed abortion, with a budget of $5,000. This year, she says they plan to spend $78 million to oppose abortion in the midterms. The group recently rebranded as Susan B. Anthony Pro-Life America to reflect a new focus on enacting state abortion restrictions once Roe is overturned.
"The conservative movement has been around since the eighties, but it's become a lot more powerful and a lot more effective," said Mary Ziegler, a leading abortion law historian at Florida State University Law School and author of "Dollars for Life: The Anti-Abortion Movement and the Fall of the Republican Establishment."
"There were decades of kind of chipping away at Roe, which have softened it for this final blow," Ziegler added. "Anti-abortion groups would try to shape who is on the court, but also give the court lots of opportunities to hollow out abortion rights."
A critical milestone was the 2016 election of Donald Trump, who explicitly pledged during his campaign to nominate justices who would overturn Roe.
"We would not be here if Donald Trump had not nominated the justices that he did. Without question," Dannenfelser said. "[Senate Majority Leader] Mitch McConnell, can be credited with holding up and waiting for an election with the Merrick Garland nomination. If Garland had been [a justice] on this case, we wouldn't we wouldn't be sitting here today."
Abortion opponents also benefitted from a critical stroke of luck: If the late liberal Justice Ruth Bader Ginsburg had retired earlier on President Barack Obama's watch, or died after Trump left office, conservative Justice Amy Coney Barrett -- a lifelong abortion rights foe -- would not have been confirmed.
"Even with the things conservatives did right, we wouldn't be here without those coincidences," Ziegler said.
As the gravity of overturning Roe comes into focus, millions of Americans who support abortion rights have been sounding the alarm, voicing outrage in public demonstrations across the country, and expressing disappointment at how the legal landscape has dramatically changed.
"It feels scary," said Shannon Brewer, director of Jackson Women's Health, the only remaining abortion clinic in the state of Mississippi, which has spent years trying to ban abortion and brought the Supreme Court case that could end Roe.
"We've been fighting all these years and it's like people say, OK, you are still open, and we are still open and doing a great job. But really, are we?" Brewer said during an interview with ABC News late last year. "How great of a job are we doing as a people, as women, as, you know, pro-choice people? How great of a job are we really doing if we're the only ones that are open?"
Outside the Jackson clinic, volunteer organizer Derenda Hancock, co-founder of the Pink House Defenders, called Supreme Court case a crude wake-up call.
"One thing that I have to give the anti-abortion protesters credit for, they are well organized, well-funded, and they stick together," Hancock said.
Abortion rights opponents, meantime, say they plan to accelerate lobbying of individual state legislatures in the months ahead, deploying armies of reinvigorated grassroots organizers to push for strict bans on abortion and the distribution of abortion pills by mail.
"The top priority is gestational limits and chemical abortion," Dannenfelser said.
Virginia is not among the 26 states certain or likely to ban abortion immediately if Roe falls, according to the Guttmacher Institute, but its Republican leaders -- elected last fall with help from SBA List -- are pushing new gestational limits on the procedure.
"Listen, we won -- and we've said all along that I'm pro-life," Virginia Gov. Glenn Youngkin told ABC News as he marched alongside demonstrators in Richmond, the first sitting governor to do so.
Some red state legislators have been calling for classification of abortion as homicide, bans on forms of contraception including the morning after pill, and possible limits on IVF treatments.
"I'm going through my own things right now with this as well. And I think everyone has to go through it, especially our generation," Stone said of IVF. "But ultimately, I don't think there's ever a justifiable reason to create an embryo and then discard it."
"From the moment that you are a human, from the moment that you have your own unique DNA, you are you. That's when you get your human rights," she said.
Dannenfelser and other national leaders in the anti-abortion movement -- cognizant of potential political blowback among moderate conservative or independent women voters -- insist bans on contraception and IVF treatments are not on the table.
"It is our job to discern how ambitious can we be and make sure that we hold the consensus. You go beyond that and you risk disaster," Dannenfelser said. "I can guarantee you there is not going to be a pro-life presidential candidate that says, I want to take away your IVF. It's not going to happen."
But millions of American women are unconvinced, vowing to fight back at the ballot box in November.
"I've heard plenty of people in the anti-abortion movement say this is not what we're for, but I don't see that stopping legislators in some states because their audience, their concerns are local," Ziegler said. "There's not really anyone in the anti-abortion movement in a position to make that promise."
The anti-abortion movement has momentum, Ziegler says, but the battle for consensus is far from over and likely to center on the Supreme Court for years ahead.
"If you care about this, you have to be willing to play the long game," she said. "We see every sign that this issue is coming back to the Supreme Court in all kinds of ways in the short as well as the long term."