Ending Roe vs. Wade opens the door to a nationwide abortion ban. But how likely is it?

House Speaker Nancy Pelosi, overseeing a very narrow Democratic majority, issued a warning to voters after the Supreme Court struck down Roe vs. Wade.

Republicans are "plotting a nationwide abortion ban" and will act if they get the majority in Congress this midterm election, she said -- a sentiment that is a nationwide rallying cry for Democrats.

And while that's possible -- the fall of Roe means abortion is no longer legally protected nationwide, leaving the door open to making it illegal nationwide -- the bigger question is whether its plausible.

Here's what to watch.

First things first: there is a Democrat in the Oval Office.

If Republicans were to win a lot of seats in the House and the Senate in November, giving them enough votes to pass a nationwide ban on abortion, that bill would still have to go to the president's desk to be made law of the land.

"The key backstop to there being a ban is that the president would veto it," said Victoria Nourse, a law professor at Georgetown University who focuses on Congress.

The only way around that, in the short-term, would be for Republicans to secure two-thirds of the Senate chamber, or 67 votes, to override that veto -- an incredibly unlikely scenario.

Still, such legislation could "very well backfire," given that only just 13% of Americans support making abortion illegal outright, according to a long-running Gallup poll, said Michele Goodwin, a constitutional law professor at University of California, Irvine.

But just because legislation is unlikely to pass in the immediate wake of the 2022 midterms, those races will still set the stage for bigger threats to abortion rights down the line.

"Where we are today is more of a marathon than a sprint," Goodwin said.

That's because if Republicans were to win the House or the Senate, they would be that much closer to enacting a ban if a Republican president was then elected in 2024.

And while Republicans could be pushed away from flat-out bans because of their unpopularity, more tailored bans could gain traction.

House Minority Leader Kevin McCarthy has thrown his weight behind a national ban on abortions after 15 weeks, which could get more support from moderate Republicans because nearly all abortions happen before then.

A ban like that could set up a "chip-away" of abortion rights, Goodwin said.

"To the extent that there is a chip-away that ultimately is realized, like what we see in Dobbs and with these trigger bans, one should actually be deeply concerned about the chip-away that could take place in Congress and also in the executive leadership of our country," she said.

Of course, the underlying question is whether Republicans would actually push for a nationwide ban, if all the pieces were in place.

So far, the only prospective 2024 candidate to go so far as call for a nationwide ban is former Vice President Mike Pence, who reacted to the Supreme Court decision by urging people not to "relent" until "the sanctity of life is restored to the center of American law in every state in the land."

Other possible Republican contenders like former President Donald Trump, former U.S. ambassador to the United Nations Nikki Haley and Missouri Sen. Josh Hawley have hailed the decision as a victory for state's rights, steering clear of mentioning top-down action at the federal level.

"This long divisive issue will be decided by the states and the American people," Trump said at a rally on Saturday in Illinois. "That's the way it should have been many many years ago, and that's the way it is now."

And Senate Minority Leader Mitch McConnell, who initially said a nationwide ban was "possible," recently said he didn't think it would be possible to get 60 senators, which is how many would have to vote in favor of a ban without ending the filibuster.

Any legislation would end up right back in court

Yet another potential barrier would be the court, which is where any law that touches the Roe vs. Wade decision would end up, whether it's an attempt to codify abortion rights or get rid of them.

And the Supreme Court ruled states should decide the laws around abortion on an individual basis, which could neuter interference at the federal level of either kind.

That's led states like California, Connecticut, New York and New Jersey to enact laws that protect peoples' rights to an abortion and make them safe harbors. It's unclear how those laws might interact with a nationwide ban -- something experts describe as uncharted territory.

But Nourse also said she sees a world where the court is more favorable to a nationwide abortion ban, which would align more with its recent ruling, than an attempt to make abortion legal.

"The bottom line is it will go back to the courts either way," said Nourse.

What about the steps to codify Roe vs. Wade as law?

While the midterms could hand Republicans a victory that set the stage for a future ban on abortion at the national level, they could also hand Democrats the votes they need to protect abortion rights.

"People across the country are mobilizing and women are pretty ticked off, including Republican women, even if they are not being vocal about this," Goodwin said.

If the decision does galvanize Democrats enough to gain seats in the Senate, progressives have urged their party to end the filibuster, which would mean Democrats could get laws passed by a slimmer majority.

This past week, Biden endorsed the idea, handing progressives a win.

But moderates warn that the political maneuver would go both ways.

Ending the filibuster could open the door to Republicans using the same tactic to ban abortion -- a point Democratic Sen. Joe Manchin leans on to defend his opposition to ending the filibuster.

The bottom line: No single election will guarantee a ban or the return of national protection for abortions, but every single one will have an impact.

"This is on the ballot," Nourse said. "And it's going to be on the ballot for a longtime."