Between 1487 and 1834, Spain’s monarchs had a legal policy of forcing religious “heretics,” like Jews and Muslims, to convert to Catholicism or die. At the height of the Spanish Inquisition, 2,000 people were burned at the stake. Today, conservative American legal scholars liken a contemporary Christian baker and business owner to those tortured forced-converts.

This bizarre argument is advanced by 34 jurists in an amicus brief (pdf) supporting petitioner (and baker) Jack Phillips in Masterpiece Cakeshop v. Colorado Civil Rights Commission, a US Supreme Court case about free speech and exercise of religion…or a case that could legalize discrimination nationwide, depending which side’s filings you believe. Today, Dec. 5, the highest court in the land will hear oral arguments in this contentious case that’s anything but a piece of cake.

The case arose from a discrimination claim based on a Colorado public-accommodations law filed to the state civil rights commission. It was filed by Charlie Craig and David Mullins after Masterpiece Cakeshop owner, Phillips, in 2012 refused to bake a cake for the couple’s same-sex marriage. Phillips argued (as he does in in his brief to the Supreme Court (pdf)) that he doesn’t discriminate against homosexuals: He’ll sell anyone confections but won’t create a cake to celebrate unions he opposes based on his faith. Baking is an artistic expression, Phillips says, and compelling him to bake for a same-sex marriage is a form of forced speech, and therefore in violation of the constitution and religious-freedom protections.

The Colorado Civil Rights Commission, a state administrative judge, and the state’s court of appeals all found in favor of Craig and Mullins. The cases were decided on the basis of the Colorado anti-discrimination law—the courts felt it wasn’t necessary to address Phillips’ arguments about free speech or freedom of religion.

The baker kept appealing, and on June 26 the US Supreme Court on agreed to grant (pdf) review, surprising legal observers. Jurists expected the Supreme Court justices to reject the request because in 2014 they didn’t review Elane Photography v. Willock, a New Mexico case finding a photo studio violated state laws by refusing to shoot a same-sex commitment ceremony.

Awkward references

Masterpiece Cakeshop pits progressives and conservatives squarely against each other in an already-divided time. The Department of Justice submitted an amicus brief for the bakery (pdf), putting itself plainly in the conservative camp by arguing that because Phillips “believes that a wedding cake is a symbol conveying a message that a marriage has begun and should be celebrated,” he can’t be forced to express support for a union he opposes based on his faith through his creative confections. Forcing Phillips to do so would be a violation of his First Amendment free-speech rights.

But the agency doesn’t go so far as to argue that Phillips’ religious freedoms were also violated because it says the free speech arguments suffice for the Supreme Court to find for the baker. Conservative legal scholars were less circumspect in this regard. They wrote a September brief (pdf) to the court rife with religious references, arguing that finding against the bakery will exacerbate national ideological divisions. By forcing Phillips and others like him to adhere to state anti-discrimination laws that put them at odds with their faith, the state will be “polluting the flow of accurate information” with “insincere affirmations” and alienating those forced to make them. This seems to be a veiled reference to fake news and information bubbles—in other words, the state will be compelling fake expressions of support for same-sex marriage by forcing businesses to all follow discrimination law and will lead to an even greater divide between left and right.

These advocates say Colorado’s anti-discrimination law forces Phillips to use his art, normally put in service of the Christian god, to publicly condone homosexuality. They go on to liken the baker to historically persecuted people forced by authorities to act against their faith. The brief claims the Colorado law is unconstitutionally compelling Phillips to choose between his truth and the law like so many before, writing:

[T]o the Jews and Muslims and “heretics” subjected to the Spanish Inquisition, or to the Christians punished and sometimes executed for refusing to pay religious obeisance to the Roman gods, or to the Jews who were punished for refusing to bow to Nebuchadnezzar’s golden statue—the proponents of the prevailing orthodoxy could always insist: “You’re making a big deal out of nothing. Nobody will assume that you actually believe what you’re outwardly seeming to affirm; they’ll know you’re just doing what the law compels you to do.”

A disturbing scene

Craig and Mullins, and their supporters, don’t see artistic expression, free speech, or religion as the relevant issues here. Instead, they say the baker is trying to use the constitution as permission to discriminate.

The American Civil Liberties Union, in its October brief (pdf) representing the respondents, says this matter is about the “routine application of a standard public accommodation law,” which simply requires businesses to accommodate all customers regardless of identity and prohibits discrimination in sales. That Colorado law “is entirely indifferent to whether the product being sold is artistic or expressive; it applies equally to sales of coffee cups or jewelry, to admissions to hotels or theaters, and to services provided by gas stations or sign painters,” the ACLU writes.

Even if Phillips really is a “cake artist” (as he describes himself) whose convictions are expressed in confections, that doesn’t legally justify discrimination, the ACLU argues. The US Supreme Court has long rejected claims that religious conviction excuses discrimination in businesses because they operate in the public space, Louise Melling, deputy legal director of the ACLU, told Quartz in a phone call on Dec. 4.

The couple points out that they—not the baker—were persecuted. “This is about much more than cake or weddings,” Mullins explained on the call. “It’s about the right of people not to be humiliated for who they are.”

When the couple and Craig’s mother, Debbie Munn, met Phillips in 2012 to discuss custom cakes, they didn’t know about the baker’s faith; their wedding planner had recommended Phillips. “It was an exciting day. My mother was going to help pick the cake. We went in with a binder full of concepts but we never got a chance to open it.” Craig recalled.

Instead, Phillips—soft-spoken, but firm—asked who was getting married, insisting he wouldn’t bake for a same-sex wedding. “There was a pregnant pause as we started to understand what was happening,” Craig said. “We were mortified, humiliated. We just gathered ourselves and left. It’s really not the kind of thing you want happening in front of your mom.”

There was no indication of Phillips’ faith on his website, Craig said. Anyway, he argued, “We weren’t asking for a statement or his art. We just wanted a wedding cake.”

Mullins sees Phillips’ rejection as equivalent to placing a sign in a shop window saying “heterosexuals only in this section.” As for the baker’s claims that he isn’t discriminating because he’d happily sell them a non-wedding confection, Mullins said, “I didn’t need brownies. I needed a wedding cake. You can’t practice your faith in a way that discriminates against customers in a public place.”

Munn was crushed by what happened to her son and his fiancé. If the high court sides with Masterpiece Cakeshop, she said, “I fear that other mothers will have to witness the pain, embarrassment, and humiliation I watched that day when I saw a stranger turn my son and his fiancé away. It was a disturbing scene.” She believes the case has consequences for many, not just her family. “No one should walk into a public place and and have to ask themselves, ‘Are we good enough to serve?'”