President Donald Trump’s imminent choice to fill the U.S. Supreme Court vacancy created by the retirement of Justice Anthony Kennedy is not likely to be much of a surprise.

Oh, the identity of the particular nominee may raise some eyebrows. But the judicial philosophy of the nominee is a given: as conservative as possible while still acceptable to a majority of senators.

One of the most talked-about issues is the likely fate of women’s right to abortion, established 45 years ago by the high court’s ruling in Roe vs. Wade.

Pundits have predicted that the end is near for Roe. And certainly these developments may have a significant impact on reproductive rights throughout the country, testing the durability of the Roe decision and its subsequent variations.

These events come at a time when abortion rates generally are falling, despite a slight uptick last year in Minnesota, and anti-abortion fervor is rising. Several states are pumping out anti-abortion legislation, such as the law enacted this winter in Iowa, the most restrictive in the nation, including a three-day waiting period, which a federal judge has halted from going into effect. Other restrictive measures are popping up, primarily in Southern states, with abortion-rights advocates challenging them in a version of legal Whac-A-Mole.

Although abortion was not a dominant issue in the 2016 presidential campaign, it played a role. As a candidate, Trump at one point supported imposing criminal penalties on women who have abortions, although he retreated a bit from that stance in one of many clarifications. He declared that he would impose an abortion “litmus test” on Supreme Court nominees.

Many abortion foes are gleeful that Trump seems undeterred in keeping these campaign pledges. His first high-court appointee, Neil Gorsuch, replacing the late Antonin Scalia, has joined his conservative colleagues in some abortion-related cases, including last month’s ruling in National Institute of Family and Life Advocates vs. Becerra, striking down a California measure requiring anti-abortion clinics to notify patients of the availability of free or low-cost abortions.

It seems beyond dispute that Gorsuch’s presence on the court ensures four solid anti-Roe votes. The departure now of Justice Kennedy, who crossed over from the conservative side in joining justices sustaining Roe over the years, raises the likelihood of a five-member majority poised to undo Roe.

Some believe it’s a sure thing. Scott Fischbach, executive director of Minnesota Citizens Concerned for Life (MCCL), began the Trump administration by prophesying that “Roe v. Wade will fall. It’s just a matter of time.”

But Roe might not be as fragile as it seems. Authored by Minnesota’s Justice Harry Blackmun, the decision held that a woman’s right to an abortion is constitutionally protected by the implicit right of privacy in the Ninth Amendment, applicable to the states through the due-process clause of the post-Civil War 14th Amendment.

Reversal of Roe may not happen easily or quickly. Supreme Court justices in general, and particularly the kind of staunch conservative whom the president is likely to nominate, are prone to follow precedent of past cases in order to maintain the stability and predictability of the law. Their visceral reluctance to reverse existing legal doctrines may impede overhauling Roe.

On the other hand, reversals are not as rare as some suspect. The high court has overturned its own rulings in whole or in part close to 150 times in its history, primarily on constitutional issues.

Memorable examples include the famous Brown vs. Board of Education case in 1954, outlawing racial segregation in public schools and sparking the civil-rights movement. The unanimous decision written by then-new Chief Justice Earl Warren overturned a 58-year-old ruling, Plessy vs. Ferguson, which had allowed “separate but equal” racial segregation.

Other noteworthy departures from precedent run the gamut. Gideon vs. Wainwright, a 1963 case granting the right to counsel in criminal cases, overruled the denial of such a right three decades earlier in Betts vs. Brady.

The infamous 1944 Korematsu decision upholding internment of Japanese-Americans as a World War II security measure was formally denounced last month by the court in upholding the administration’s travel ban in Trump vs. Hawaii, although the author of the opinion for the court, Chief Justice John Roberts, declared Korematsu to have been long since overruled by the “court of history.”

Of perhaps greater contemporary significance, the flipping of precedent by the Supreme Court in its decision three years ago upholding the right of “same-sex” marriage in Obergefell vs. Hodges, authored by Kennedy, overruled its prior view in 1972 that the issue lacked “substantial” constitutional status. The earlier decision dismissed an appeal of a ruling by the Minnesota Supreme Court rejecting a challenge to the exclusive male-female marital relationship in Baker vs. Nelson.

That said, in most cases, even controversial ones, the Supreme Court adheres to precedent. For example, the landmark Miranda vs. Arizona case (decided during the heyday of the liberal-leaning Warren court of the mid-1960s), barring improperly obtained confessions and establishing those well-known warnings to criminal suspects, was a target of conservative forces for years, especially because it was decided by a slender 5-4 margin. But when the issue resurfaced 34 years later in Dickerson vs. United States, the high court reaffirmed Miranda by a decisive 7-2 vote, with the majority decision written by Chief Justice William Rehnquist, a longtime Miranda foe. Rehnquist regarded the ruling, which he fought for years to limit or overturn, by then to be so deeply ingrained in the “national culture” that it was impervious to dismantling.

As Rehnquist’s ruling reflects, fidelity to following existing law is a hallmark of the high court. It is a time-honored principle to which all of the jurists pay lip service and sometimes more. For instance, a year before Roe, the court upheld a widely discredited 50-year-old precedent that Major League Baseball is not subject to antitrust law. The author of the majority opinion, Minnesota’s Blackmun again, thought the tenet unsound. Nevertheless, he upheld the five-decade-old precedent under the rubric of “stare decisis,” the hoary legal doctrine that courts should generally favor the status quo in the interpretation of the law.

Beyond the power of precedent, the formidability of the Roe decision may be grounded on the solid support it garnered at the time. Contrary to popular misconception, Roe was not a narrowly divided 5-4 liberal-vs.-conservative decision. Blackmun’s majority decision was approved by a 7-2 vote. Even Chief Justice Warren Burger, another Minnesotan and an ardent conservative, joined in the ruling, although with some expressed misgivings.

The underpinnings of Roe were solidified 19 years later when the high court expressly reaffirmed the ruling in Planned Parenthood vs. Casey, a decision in which Justice Kennedy cast a decisive vote in favor of upholding Roe.

Thus, Roe vs. Wade may be endangered, but it does not hang by as slender a reed, as some might fearfully, or hopefully, surmise.

But despite the ruling’s sturdiness, anti-Roe jurists might be able to chip away at its underpinnings without expressly overruling it, eventually leaving the doctrine vulnerable to being dismantled.

This is precisely what happened last month when the justices capped a four-decade assault on the posture of labor unions by ruling in Janus vs. AFSCME that public-sector employees cannot be required to pay union dues for the benefits of union efforts they enjoy without being members. The decision struck down laws in 22 states, including Minnesota, on grounds that forcing workers to pay dues without their consent constitutes an “unconstitutional exaction” that violates the objectors’ First Amendment right of freedom of expression, a rationale that dissenting Justice Elena Kagan caustically derided, in terminology more accustomed to conservatives preaching judicial restraint, as a “weaponizing of the First Amendment” by “black-robed rulers.”

That decision, another 5-4 ruling, overturned the 1977 case of Abood vs. Detroit Board of Education, which had held that dissenting union members must pay “fair share” dues without being assessed the portion of dues attributable to supporting political candidates or causes. The Janus ruling gives objectors “free rider” status, entitled to all of the benefits of union membership, such as negotiation of wages and other terms of employment, without paying anything for them. It’s like an all-you-can-eat smorgasbord with no cash register at the end of the line.

But that demolition of precedent, which represents a substantial setback for public-sector unions and has unfavorable reverberations in the private sector, did not come out of the ether. It was the culmination of a few high-court rulings that eroded the Abood principle and made it easy for the justices to topple it without too much blatant irreverence for precedent.

The justifications for overturning precedent in the Janus case, written by longtime union foe Justice Samuel Alito, are ominous for Roe supporters. He cited the “fundamental” nature of the rights at stake in the case and argued that the prior Abood decision was “poorly reasoned,” that the ruling led to “practical problems and abuse” and that its posture has been undermined by more recent decisions. Many of those rationales could be deployed against Roe.

As for Minnesota, efforts to curb abortion rights here have been limited to marginal matters: restrictions on minors; parental consent, and waiting periods. Significant issues, to be sure, but not catastrophic for reproductive-rights advocates.

But the outcome of the current election cycle may usher in renewed emphasis on abortion issues, depending upon the new composition of the Legislature and the identity of the governor.

So whether Roe is doomed or destined to survive, in one form or forum or another, is an resolved question as we await President Trump’s announcement. In the oft-used phrase of the president himself: “We’ll see what happens.”

Marshall H. Tanick is a Twin Cities constitutional law attorney.