On its face, it sounds like the epitome of a frivolous, if not blasphemous, lawsuit: A group of Satanists in Missouri sued the state over its strict anti-abortion laws on religious-discrimination grounds. A state trial court agreed, sort of, dismissing the case not long after it was filed in 2015.

But skepticism about The Satanic Temple's suit against Gov. Eric Greitens, a Republican, and Show-Me State administrators ended when the Satanists appealed, the state Supreme Court agreed to take the case – and, based on the arguments presented in court, experts say the Satanists could actually win.

If they prevail in the case, an organization named for the Dark Lord of the Underworld could upend a 2016 law requiring women to wait 72 hours before an abortion, forcing doctors to give women ultrasounds of the fetus and offering them literature declaring that "life begins at conception."

Although the state's highest court won't rule for several weeks, the group has already claimed a big victory: It says the state did a 180 on the ultrasounds during oral arguments, acknowledging that they're voluntary and not mandatory.

"It's kind of ironic," says Mary Ziegler, a Florida State University law professor who specializes in women's rights issues. "This is showing that people on both sides of the political spectrum can use religious freedom" to challenge laws they don't like.

Adding to the irony: Members of The Satanic Temple don't really believe in Satan.

Though the organization is described as dedicated to Satanic practice and promotion of Satanic rights, it's actually a progressive political organization that sees the biblical Satan as a metaphor, and their mission as rebellion against tyranny.

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Its mission statement calls for members to be "politically aware" and "encourage benevolence and empathy among all people, reject tyrannical authority, advocate practical common sense and justice, and be directed by the human conscience to undertake noble pursuits guided by the individual will." The organization says it has worked for women's rights and against persecution of gays, corporal punishment in schools and insertion of religion in public life, among other progressive causes.

Regardless of the outcome, the Mary Doe-Satanic Temple case could provide a template for the political left to battle so-called "religious freedom" laws - red-state statutes passed in recent years that liberal critics say force conservative Christian values on society writ large, an escalation of the so-called culture wars.

"Oh, yeah, I can see it working" in other states, says Ziegler. "One hundred percent – especially if they [the Satanists] win. There will be other lawsuits like this" in states where the higher courts tilt to the left, and may want to prove a point about the use of religion to form public policy.

"I think this is sort of a signal if we're going to have a robust religious [influence on] jurisprudence, it's going to cut both ways," she says.

At issue is the case of Mary Doe, an anonymous Southern Missouri woman who in March 2015 learned she was pregnant. She saved up enough money to travel to St. Louis and rent a hotel room, then made an appointment at a clinic in the city.

On May 8, 2015, Doe "made her first visit to the abortion clinic, and delivered a letter purporting to waive the Informed Consent Law requirements according to her Satanic beliefs," according to a case summary in the court file. Among those beliefs: "That a non-viable fetus is not a separate human being but is part of her body and that abortion of a non-viable fetus does not terminate the life of a separate, unique, living human being."

The clinic refused to give her an abortion, "but it offered Doe the Booklet and gave Doe an ultrasound" and had her listen to the fetal heartbeat, as required under state law.

Having read the booklet, Doe had to wait 72 hours before trying again, according to the documents, during which she "alleges that she felt guilt and shame." She returned to the clinic and had the procedure – but not before suing the state during the waiting period, contending the requirements of the state's Informed Consent Law violates her rights under Missouri's Religious Freedom Restoration act.

The text of that law says that the state cannot "substantially burden a person's exercise of religion" – in this case, Doe's membership in the Satanic Temple – unless it is furthering a "compelling government interest" and acting in the least restrictive way possible. The state attorney general's office, which is defending the abortion law, argues that Missouri's religious freedom laws don't apply in this case.

During oral arguments, the state argued that Doe and the Temple failed to show or argue any conflict between her "putative Satanic beliefs" and the state's law. At the same time, one of the appellate judges noted that the clinic only had to give Doe the booklet; the law doesn't require doctors to make her read it.

But James MacNaughton, an attorney for Doe, reportedly told the state Supreme Court that the government "should not be in the business of preaching" to its citizens.

"It is a bedrock principle of our culture (and) of our country that we choose for ourselves what to believe by way of religious beliefs," he said. "It's not the business of government to tell us that."

The case took a sharp turn, however, when John Sauer, the state's solicitor general, told the court that the ultrasound and fetal heartbeat components of the law were voluntary.

After the hearing, the Temple released audio of the hearing in which Sauer acknowledges that, in his interpretation, the law's requirements have been met if a woman is merely offered the "opportunity" to listen to the fetal heartbeat; if she declines, she doesn't have to have the ultrasound.

Though the Missouri Supreme Court will decide the case in the coming weeks, Ziegler, the Florida State law professor, believes the Satanists have reached an important milestone.

"A lot of pro-choice groups haven't put emphasis on religious claims because they've been defeated by the Supreme Court," which in the past has rejected spiritual beliefs as a justification for abortion, she says.

But the Satanic Temple's arguments in the Missouri case, Ziegler adds, "got a big boost" from the Supreme Court's 2014 ruling in Burwell v. Hobby Lobby, in which the justices ruled that the craft-supply store chain – founded and owned by evangelical Christians – didn't have to abide by an Affordable Care Act mandate to offer birth control to its employees.

That ruling "can cut the other way and it can benefit other parties" Ziegler says. Other abortion rights and progressive organizations, she says, likely are watching the Satanic Temple case closely, and could decide to use the religious-freedom argument in other states.