In an interview with CBS’s Leslie Stahl on 60 Minutes, President-elect Donald Trump said he would appoint “pro-life” judges to the Supreme Court — and that if Roe v. Wade were overturned, women would “have to go to another state” if they want an abortion.

“If [Roe v. Wade] ever were overturned, it would go back to the states,” Trump said.

Stahl followed up: “But then some women won’t be able to get an abortion?”

“Yeah, well, they’ll perhaps have to go — they’ll have to go to another state,” Trump said.

“And that’s okay?” Stahl asked.

“Well, we’ll see what happens,” Trump said. “It’s got a long way to go.”

While Trump used the word “if” here, he has made clear before that he believes nominating “pro-life” judges will “automatically” result in Roe v. Wade being overturned at some point. For Trump, overturning Roe seems to be a question of “when” rather than “if.”

Roe v. Wade has been Supreme Court precedent for 43 years. But when Stahl asked Trump about same-sex marriage, which the Court legalized last year, his response was very different.

“It was already settled. It’s law,” Trump said. “These cases have gone to the Supreme Court. They’ve been settled. … I’m fine with that.”

As my colleague German Lopez has explained, a Trump-Pence administration could actually be a nightmare for LGBTQ Americans, even though Trump has made occasional (and often clumsy) efforts to reach out to that community.

But Trump has been a lot more explicit about how his administration would roll back reproductive rights. He has promised to appoint justices who will overturn Roe v. Wade. And although he quickly walked it back after massive pushback, he said that women would face “some form of punishment” if abortion were outlawed.

The real question, then, isn’t whether Trump is serious about opposing abortion. It’s how much he can actually do about it.

When it comes to Roe v. Wade specifically, it’s a little complicated. Roe probably wouldn’t be overturned in the next four years, and maybe never. But depending on how many justices Trump gets to appoint, and depending on which cases the Court decides to hear, Roe could very well be in danger in the medium- to long-term.

Why Roe v. Wade is probably (probably) safe

Julie Rikelman, litigation director at the Center for Reproductive Rights, put it plainly to Vox in an interview: “I do not believe that it is likely that Roe v. Wade would be overturned,” she said.

There are three major reasons for this, she said:

The power of precedent

“Roe v. Wade has now been the law of the land for over 40 years,” Rikelman said. “It has lasted through a number of anti-choice administrations, including those who vowed to put justices on the court that would overturn Roe v. Wade. And in those over 40 years, many cases have come up to the Supreme Court where there was a request for Roe v. Wade to be overturned, but it wasn't.”

In other words, the Court has had opportunities to overturn Roe before. But it hasn’t taken them. And a key reason why, Rikelman said, is that “the institution of the Supreme Court gives a lot of weight to precedent and to something called stare decisis. And that means that when the Supreme Court has interpreted the Constitution and issued an opinion, that opinion is supposed to remain in place unless there are very, very, very, very good reasons for revisiting it.”

There have been many Supreme Court justices over the years who personally oppose abortion. One of them is Anthony Kennedy, who is typically the “swing vote” between the liberal and conservative factions on the current Court.

But Kennedy has voted to uphold abortion rights in two essential cases: 1992’s Planned Parenthood v. Casey, which many abortion opponents had hoped would be the case to overturn Roe, and this year’s Whole Woman’s Health v. Hellerstedt, which gave pro-choice advocates a huge victory over restrictive state-level abortion regulations that are designed to force clinics to close.

Casey, it’s important to note, did weaken Roe v. Wade. Under Roe, states couldn’t interfere at all with a woman’s right to choose before a fetus is viable, or roughly the third trimester. But after Casey, the courts ruled that states can regulate abortion at any point during pregnancy — as long as it doesn’t present an “undue burden” to a woman seeking an abortion. (This fuzzy standard has allowed some restrictions, like waiting period and parental notification laws, to stand. But Whole Woman’s Health made clear that some laws, like targeting clinics with absurdly restrictive building codes, go too far.)

But with Casey the court still upheld the fundamental right to an abortion, and precedent is a key reason why, Rikelman said. It was because “decades of women had come of age and organized their lives with the understanding that they have this basic right to make personal decisions, and to control their own bodies, and to be able to have jobs, and be able to participate in the social and economic life of the nation. That's how the Court talked about it.”

Of course, anti-abortion justices also voted the other way and wrote dissents in those two pivotal cases, Casey and Whole Woman’s Health. But the power of precedent is still a significant barrier to overturning cases as long-lasting and pivotal as Roe.

Many justices over the years, regardless of their personal views on certain issues, have said that “respecting precedent is a huge part of maintaining the integrity of the institution,” Rikelman said.

The alignment of the current Court

After the death of conservative stalwart Antonin Scalia, and the refusal of Republicans in the Senate to hold hearings on President Obama’s proposed replacement Merrick Garland, there are still only eight justices on the Supreme Court. That means Trump will probably appoint the ninth — and it’s probably safe to assume that that ninth justice will be an “ultra-conservative” who favors overturning Roe.

But even then, Rikelman said, the Court still has a five-member majority that clearly would not vote to overturn Roe: the four liberal justices and Anthony Kennedy, who recently voted with them in Whole Woman’s Health to strengthen abortion rights.

If one of those five members retires or dies while Trump is in office, the balance could shift. But Rikelman said she believes the power of precedent would keep Roe standing even if Trump appoints two justices who are committed to overturning it.

The difficulty and rarity of actually getting the Court to hear a case

So let’s say Trump has appointed those two ultra-conservative justices, and that all three of the other conservatives on the Court are willing to join them and set precedent on fire by overturning Roe v. Wade.

They still need to hear the right case that will allow them to do that.

“A case can't just sort of show up two weeks from now at the Supreme Court that would allow it to overturn Roe v. Wade,” Rikelman said. “There are rules about when the Supreme Court takes cases, and it takes very, very few of the cases that come before it — a tiny percentage. And so it could be many years before a case even came in front of the Court that would give it the opportunity to overturn Roe v. Wade.”

Generally speaking, the Supreme Court only takes a case if one of two things happen, Rikelman said.

One is a “circuit split,” when two lower federal courts of appeals disagree on an issue of law. That’s why the Court took up Whole Woman’s Health in the first place, Rikelman said. Every federal appeals court except one, the 5th Circuit Court, which governs Texas, Louisiana, and Mississippi, had struck down abortion restrictions that were similar to the ones Texas passed in 2013.

So there was a conflict that the Court had to resolve, which it did — but it took three years after Texas passed its anti-abortion laws for that ruling to come down.

The other scenario in which the Court might step in is when a federal law passes that gets challenged as unconstitutional. That’s actually a pretty likely scenario with a Republican-controlled Congress and Trump as president.

Republicans in Congress have been trying for several years to pass a national 20-week abortion ban. It’s also very possible, given the latest anti-abortion lawmaking trends at the state level, that Congress would try to pass a national ban on dilation and extraction (D&E), the safest and most common method of performing a second-trimester abortion. A D&E ban wouldn’t explicitly outlaw second-trimester abortion, but the practical effect would be almost the same.

Both of those laws would fly in the face of Roe because they would ban abortion, either outright or effectively, before a fetus is viable. So either of those laws would probably be challenged.

Even in this circumstance, though, “the cases do not necessarily move that quickly through the courts,” Rikelman said. “The application can take a long time.”

Why Roe v. Wade might be in trouble

Jessica Mason Pieklo, a constitutional law expert and legal analyst for the reproductive rights news site Rewire, agrees with everything Rikelman said about precedent, the Court’s current pro-choice majority, and the barriers to actually getting the Court to hear a case.

For all of these reasons, Mason Pieklo agrees that Roe will probably be fine in the short term. But longer-term, she’s less optimistic that Roe will ultimately survive a Trump-appointed Supreme Court intact.

“Roe is under threat, both directly and indirectly,” she said.

The key thing to understand is that Roe v. Wade doesn’t have to be directly overturned for its protections to become meaningless. We’ve already seen hints of what this looks like in states like Texas that regulated abortion out of existence in certain areas, or states like Mississippi where regulations are so stringent that there’s only one abortion clinic left in the entire state.

But from a national perspective, take the example above where Congress passes a 20-week abortion ban or a D&E ban and Trump signs it, Mason Pieklo said.

Pro-choice advocates have two options if that happens. They can either let the law go into effect and see abortion rights for American women be dramatically reduced nationwide — or they can challenge the law at the Supreme Court. But if Trump gets the five-plus member ultra-conservative majority he’s angling for, a challenge like that could either be very risky, or doomed from the start.

To further complicate matters, Mason Pieklo said, it’s possible that either of those anti-abortion laws, a 20-week ban, or a D&E ban could be upheld under Casey’s lower standard without actually overturning Roe.

In that scenario, women would still nominally have a right to abortion in America.

But if a 20-week ban is upheld, that would mean that if a woman discovers a devastating fetal anomaly at her 20-week ultrasound, she’d have to leave the country to end the pregnancy.

And if a D&E ban is upheld, if a woman doesn’t find out that she’s pregnant until she’s more than 12 weeks along or can’t get the money for an abortion together until then, she would need to find a doctor willing to perform an abortion procedure that puts her at unnecessary risk, which might require crossing state lines. Or she would have to leave the country. Or she would just be out of luck.

So in a nutshell, abortion rights aren’t doomed for sure after Trump becomes president. But they are by no means safe.

Update: This article’s headline has been updated to clarify that Trump talked about overturning Roe v. Wade as a possibility, not a certainty, in his interview with Stahl.

Watch: It’s up to America’s institutions to check Trump