On Tuesday, the Supreme Court struck down a California law regulating antiabortion crisis pregnancy centers, which are Christian counseling centers that try to persuade women to continue their pregnancies. California had required pregnancy centers with a medical license to tell women that the state provided free or low-cost services, including abortion, to low-income women. If a center wasn’t licensed, the facility had to post a sign saying so.

For all the justices, the case boiled down to a question of fairness. Writing for the majority, Justice Clarence Thomas accused California of discriminating against Christians. After all, the state demanded that crisis pregnancy centers — and no similar facilities — post notices about other services. Justice Stephen G. Breyer argued that the discrimination actually ran the other way: The Supreme Court had upheld laws requiring abortion providers to recite a state-mandated script but wouldn’t do the same when antiabortion activists made their case.

Breyer’s argument reveals an inconsistency in the court’s approach to crisis pregnancy centers. The court is allowing these centers to have it both ways: to claim the protections of a religious entity while being allowed to dole out medical advice. That leeway stands in sharp contrast to the mounting restrictions placed on abortion providers.

The history of debate about pregnancy centers — and abortion clinics — helps explain how we got here. Starting in the early 1980s, antiabortion lawyers realized their fetal-rights arguments weren’t working. So they changed their pitch to the Supreme Court, arguing that only when abortion regulations unduly burdened women should the court strike them down. In defending restrictions on abortion procedures, they insisted that many abortion doctors did not really practice medicine at all, instead making money by misinforming women and performing harmful procedures.

Later in the 1980s, as crisis pregnancy centers rapidly spread, abortion rights supporters launched a similar campaign. Sending undercover activists to the centers, supporters of legal abortion insisted that some facilities advertised themselves as medical facilities without providing any such services. Worse, they argued, staff did not disclose their religious beliefs or opposition to abortion. These centers, the argument went, harmed women by providing them with inaccurate information about their medical options.

By the late 1980s, then, the legal battle over abortion was less about the lawfulness of the procedure than the regulation of each side’s facilities.

In the 1990s, it was hard to tell which side was winning. The Supreme Court upheld a Pennsylvania law requiring doctors to recite a state-authorized script before performing an abortion. In the same period, state attorneys general brought criminal prosecutions against pregnancy center operators, citing deceptive trade practices. Democrats in Congress also launched an investigation of these centers, labeling them “phony clinics.”

After the Supreme Court refused to overturn Roe v. Wade in 1992, crisis pregnancy centers became more popular in antiabortion circles. At a time when progress seemed stymied politically and in the courts, the centers offered another route for reducing abortions: persuading individual women to continue their pregnancies.

Crisis pregnancy centers also changed their branding. They had avoided embracing a religious identity for fear of seeming too Catholic. But as the movement diversified and secular arguments against abortion failed, activists leaned more heavily on religious arguments. They also began asserting that abortion damaged women’s health. Staff increasingly told women that abortion might increase the risk of future infertility or even breast cancer. Abortion foes hoped these new claims might compel courts to endorse greater restrictions and scare women away from abortions.

Antiabortion activists also sought to convince both voters and judges that abortion doctors were not really doctors at all. To a limited extent, they found a receptive audience on the Supreme Court. Over the last 15 years, the court has justified regulations of abortion providers by hinting that they might not be as professional as they ought to be. In particular, some of the justices have worried that abortion doctors might deprive patients of crucial information, reflecting a lack of medical professionalism.

This argument gained traction partly because antiabortion activists had successfully stigmatized the abortion procedure. Abortion rights forces had been reduced to arguing that abortion be safe, legal and rare. As abortion practice shifted from doctors’ offices and hospitals to free-standing clinics, it was easier for antiabortion advocates to describe abortion as a procedure that did not resemble other health-care services.

Tuesday’s decision forced the court to address whether crisis pregnancy centers should be regulated as much as abortion clinics. California had argued the centers masqueraded as medical clinics, misleading poor women who did not understand the full range of available choices. Pregnancy centers countered that they were not, in fact, offering medical advice but rather delivering a political or even religious message.

But that argument revealed an untenable contradiction at the core of the centers’ positioning. If they are political or religious entities, the government faces a far greater bar for restricting their speech, but it could limit their ability to spread a message about the medical dangers of abortion. And women might rely less on medical statements made by the centers. After all, women would be far less likely to seek medical advice from a political organization or religious group. But if the staff are medical experts, the court could treat employees just like abortion providers — allowing the government to regulate their speech.

The Supreme Court majority avoided addressing this contradiction by saying almost nothing about what crisis pregnancy centers do, allowing them to continue having it both ways. When women come seeking support, staff can inform them about the medical risks of procedures without identifying if they are medical experts. And when pregnancy centers come to court, they can pivot, and present themselves as religious entities persecuted by states that denigrate their faith.

If the justices want to adjudicate these issues fairly — and that might be a big if — this isn’t a tenable position for the court. The court has weighed in on what abortion providers do. The justices should similarly address the real-world practices of pregnancy centers. If, as the conservative justices contend, they function more like a church or religious-outreach organization, then they do warrant different treatment from abortion clinics. Practicing a religion is not, after all, the same thing as practicing medicine.

But the court’s decision to treat crisis pregnancy centers as religious institutions has created two  contrasting sets of rules when it comes to free speech on abortion. While abortion providers have their speech rights curbed — they are required by law to say certain things to their patients — the majority seemed to suggest that crisis pregnancy centers are different. That may be true. But the court cannot convincingly make this case until it has evaluated what these centers do in precisely the manner it has evaluated abortion clinics. If it fails to do so, abortion rights supporters will have more than enough cause to feel the court is playing politics in one of our most fraught political debates.