The Supreme Court was something of an under-the-radar issue in the 2016 campaign, extremely important to some groups (especially white evangelicals), but not discussed all that much on a national level. But now that Donald Trump has been elected, and with the success of the GOP's only-Republican-presidents-are-allowed-to-fill-vacancies strategy, it will be of tremendous importance to the country's future.

No issue will be more volatile than abortion, which raises the inevitable question: Is Roe v. Wade doomed?

That question is coming up again in the wake of the Ohio legislature's shocking decision to pass a ban on abortions once a fetal heartbeat can be detected, which is usually about six weeks into a pregnancy, before many women even know they're pregnant. Under current jurisprudence, this ban is almost certainly unconstitutional. But maybe by the time it reaches the Supreme Court, it won't be.

If you listen to some pro-choice activists, Roe is still safe, for now. As Julie Rikelman of the Center for Reproductive Rights recently told New York magazine, "We definitely need to be concerned, but we do not believe that Roe v. Wade would be overturned at this point in time."

The idea is that not only are the justices reluctant to overturn the Court's precedents, but they're also attuned to public opinion and political reality, and understand what upheaval would result if they overturned Roe. Ruth Bader Ginsburg said as much in an interview last year: "This court is highly precedent bound. And it could happen, but I think it's not a likely scenario."

I suspect that pro-choice groups may be taking that line in part to persuade the justices of just that argument. Unfortunately, it's much more likely that by the time we get to the end of Donald Trump's term, Roe will be history.

Here's where we stand right now. There are five votes to maintain Roe: the liberals Ginsburg, Sonia Sotomayor, Elena Kagan, and Stephen Breyer, and the swing voter Anthony Kennedy. There are two iron-clad votes to overturn Roe: Clarence Thomas and Samuel Alito. Donald Trump has made it clear he'll be appointing a "pro-life" justice, and there's simply no way conservatives would let him get away with naming someone to fill Antonin Scalia's seat who wasn't guaranteed to vote against Roe .

That's three votes against Roe . Now let's imagine that at some point in the next four years, Ginsburg (age 83), Breyer (78) or Kennedy (80) leaves the Court. Their replacement would also be all but guaranteed to be a vote to overturn Roe. That's four. Which means it all comes down to John Roberts.

No one knows for sure how he'd rule. On one hand, Roberts is extremely well-attuned to the politics of the moment and reluctant to issue rulings that would cause political chaos and undermine the authority and legitimacy of the Court. He is surely well aware that in polls the idea of overturning the decision is usually opposed by at least 60 percent of the public and sometimes more.

On the other hand, Roberts was nurtured in the Reagan Justice Department, where he participated in many efforts to restrict abortion rights. While he made all the right noises about Roe being settled precedent during his confirmation hearings in 2005 (as every conservative justice does ), he has never joined the pro-choice side of a decision before the High Court.

Earlier this year, he dissented in a case that struck down a set of absurd restrictions Texas had placed on abortion clinics, a classic "TRAP law" (Targeted Regulation of Abortion Providers), in which the state places regulatory demands that are all but impossible to satisfy on abortion clinics as a way of driving them out of business.

That Texas law was so ridiculous that if you believed it was constitutional - as Roberts, Thomas, and Alito did - then there's essentially no restriction on abortion rights you'd find unduly burdensome. Which suggests that Roberts will be perfectly ready to discard Roe if he gets the chance.

But that case also suggests something else: the conservatives on the Court, joined by their new colleagues (if Trump gets one more appointment) could effectively overturn Roe without actually overturning Roe.

They could claim that Roe still stands while gutting the standard set out in Planned Parenthood v. Casey, which said that states can't place an "undue burden" on a woman's right to choose.

They could say that "heartbeat" bans like Ohio's are fine, as are TRAP laws that make it impossible to open an abortion clinic, as are lengthy waiting periods or requirements that doctors lie to their patients and tell them that if they have an abortion they'll go mad and die from cancer.

With five anti-abortion votes, they could create the functional equivalent of a world without Roe , where abortion is all but illegal in states controlled by Republicans but legal in states controlled by Democrats.

Here's the last part of the puzzle, which leads to the possibility of an even more frightening scenario. Now that Republicans control Congress and the White House, they aren't going to be waiting around: they're likely to pass national laws on abortion, things like bans after 20 weeks, national waiting periods, and other laws meant to make abortion as difficult and cumbersome as possible for women, particularly poor women, to obtain.

When you add in the Republican Congress, you could envision a scenario even worse than Roe being overturned. Here's how it would work:

• With another retirement, the Supreme Court reaches five anti-choice votes.

• Instead of overturning Roe v. Wade, they gut the undue burden standard in Casey.

• Congress then passes a series of incredibly restrictive abortion laws, on things like clinic standards, waiting periods, and a version of Ohio's "heartbeat" bill, or at least one outlawing abortion after some small period of time, perhaps not the 20 weeks that's now discussed but 15 or 10.

This is worse because if Roe were simply overturned, each state could make its own rules, which means abortion would still be legal and available in states controlled by Democrats. But under this scenario, every state would live under the rules set by Republicans in Congress, who are almost unanimous in their desire to see abortion rights disappear completely.

Would there be a political backlash? Absolutely. That prospect might be enough to restrain Republicans from reaching for their heart's desire. But there are some very dark days ahead for reproductive rights.