A Supreme Court ruling in favor of Masterpiece Cakeshop would destroy discrimination law.

On Dec. 5, the Supreme Court will hear oral arguments in the term’s blockbuster case, Masterpiece Cakeshop v. Colorado Civil Rights Commission, which revolves around a bakery that refused to sell a custom wedding cake to a same-sex couple. The bakery’s owner, Jack Phillips, seeks an exemption from Colorado’s civil-rights law, which prohibits public businesses from discriminating based on sexual orientation. He argues that this is a narrow case about whether the government can “compel artists to create expression that violates their sincerely held religious beliefs about marriage.”

Don’t believe it. All of Phillips’s attempts to limit the case fall apart under scrutiny.

First, Phillips says this case is about “artists.” As a cake maker, he consults with clients to discern their personalities and preferences, sketches a design, molds the cake into shape, and decorates it with ornaments. This, according to his lawyers, makes him “a modern painter or sculptor.” Attempting to pre-emptively refute the obvious slippery slope argument here, Jeff Sessions’ Department of Justice submitted a brief in support of the cake shop, reassuring the court that a commercial banquet hall, limousine service, or hotel could not make the same claim.

But under Masterpiece Cakeshop’s reasoning, surely they could. Many wedding venues consult with clients to discern their personalities and preferences, develop a bespoke room layout, and adorn the reception space with customized décor. Who can confidently say that any profession is devoid of creativity? More pointedly, who believes the Supreme Court is best equipped to choose the artists among us?

Second, Phillips tells us this case is about “expression.” He cites cases where individuals successfully challenged laws that forced them to convey views they did not hold, such as the Jehovah’s Witnesses who objected to having New Hampshire’s slogan “Live Free or Die” stamped on their license plates. Yet baking a cake is not pure speech: It is at most intermingled speech and conduct. (As David H. Gans wrote recently in Slate, Chief Justice John Roberts has repeatedly held that such intermingled speech does not face the same scrutiny as pure speech.) The Colorado law does not force Masterpiece Cakeshop to stamp a pro-gay slogan on its storefront. It does not force the shop to make wedding cakes at all. It only requires that if the business sells wedding cakes to straight couples, it must sell them to gay couples, too.

Third, Phillips tells us this case is about violations of “sincerely held religious beliefs.” In a nation as religiously diverse as ours, that is hardly a limitation. In a 1990 case interpreting the Free Exercise Clause, Justice Antonin Scalia wrote that courts cannot grant exemptions from laws that apply to all simply because they burden the free exercise of some. “Any society adopting such a system would be courting anarchy,” he said, “but that danger increases in direct proportion to the society’s diversity of religious beliefs.” Justice Scalia cited a dozen court cases in which litigants had sought religious exemptions from laws such as those barring “animal cruelty,” “child labor,” and “manslaughter.”

Fourth, Phillips assures us that his case is only about “marriage.” He claims a willingness to create other items for gay customers, including cakes for baby showers or birthdays. That may be true of Phillips. Yet if the court grants his business this exemption, others will not be so accommodating. Gay couples could face cradle-to-grave discrimination. Consider the pediatrician who refused to treat the child of a same-sex couple and the funeral home that refused to cremate a deceased gay man. If the court rules that businesses may discriminate against gay people exercising their constitutional right to marry, how could it forbid businesses from discriminating against gay people in other contexts?

Fifth and finally, Phillips’s brief contains no discussion of the implications of this case for categories other than sexual orientation, even though the Colorado law also bars discrimination on other bases such as race, sex, and disability. The omission is telling as it is impossible to carve out a “gay exception” to the list.

In 1964, the barbecue franchise Piggie Park denied service to several black customers, who brought suit under the newly minted federal Civil Rights Act. The owner, Maurice Bessinger, was the head of the National Association for the Preservation of White People. He maintained that he had “a constitutional right to refuse to serve members of the Negro race in his business establishments upon the ground that to do so would violate his sacred religious beliefs.” The court swiftly rejected this contention, distinguishing Bessinger’s absolute right to his beliefs from his right to exercise those beliefs in a manner that trammeled the legal rights of others.

If the court finds a religious right to discriminate against gay people, how will it forestall a religious right to discriminate against racial minorities? At a time when our president sees “very fine people” at a white supremacist rally, we can all but assume such cases will arise. The government’s brief implicitly acknowledges this prospect when it says that racial civil-rights laws “may” survive an analogous constitutional challenge.

Phillips and the Trump administration insistently characterize this case as a narrow one. But the thin end of any wedge always looks narrow. A ruling in Phillips’ favor would insert that wedge into the edifice of civil-rights law, with results as disastrous as they are foreseeable.