In Masterpiece Cakeshop v. Colorado Civil Rights Commission, the Court will determine whether a baker can decline to provide a cake for a same-sex wedding, despite Colorado’s law against discrimination based on sexual orientation.

The baker, Jack Phillips, has two arguments: that the Free Exercise Clause allows “believers” a “freedom to live out their religious identity in the public square” and that Colorado is forcing him to “create art” he finds morally repugnant. Just as the state cannot force children to recite the Pledge of Allegiance, or its drivers to display its motto, so it cannot command Phillips to ventriloquize a message of tolerance he repudiates.

Despite its courting of evangelical voters, the Trump Administration sides with Phillips on his speech argument, but not his religious liberty argument. This is a signal that the culture-war component of the case will not prove decisive.

The Supreme Court has long looked askance at constitutional claims for religious exceptions to generally applicable laws. As Justice Antonin Scalia pointed out in a 1990 opinion, it would be unmanageable to have a legal “system in which each conscience is a law unto itself or in which judges weigh the social importance of all laws against the centrality of all religious beliefs.” Scalia’s logic likely still holds sway for the justices, and suggests that those sympathetic to Phillips may seek another path.

Hence the appeal of Phillip’s argument that Colorado is compelling him to speak by wielding ribbon cutters, extruders, and fondant cutters to celebrate a gay nuptial. This may seem attractive to some justices. But an opinion on these grounds would have to navigate several serious difficulties, distort the facts of the case, and might open an equally destabilizing litigation front—this time in respect to commercial regulation.

A first problem is whether Colorado is even compelling Phillips to speak. When a vendor produces a product for a customer, we usually don’t think she’s thereby expressing her own views. Moreover, unlike other laws invalidated as compelling speech, anti-discrimination norms don’t require behavior with a single message: A refusal to deal with a same-sex couple sends a very different message than a decision not to hire a Mormon because of her faith—yet both are illegal in Colorado.

And then, there is a puzzling gap between the evidence in the case and Phillips’ First Amendment claim. His brief suggests that he was asked to—and refused to—“design” a cake. But the record suggests that the gay couple never asked Phillips to “design” a cake—just to sell them one. Although reasonable people can disagree about what ought to count as speech protected by the Constitution, the mere fact of selling someone a commodity doesn’t obviously count.

But what if the Court holds that it does? Here’s the intriguing part: A holding that respects the record in Masterpiece might imply that a decision to trade in the marketplace is a kind of “speech” protected by the First Amendment. But there’s an enormous amount of regulation around decisions to trade—ranging from antitrust to much ordinary contract law—that equally regulates the same kind of “speech.”

A free-speech ruling in Masterpiece is very unlikely to invalidate all that law. But it will require the Court to draw some sort of line around when commercial activity counts as “speech.” But where? And on what grounds? Just as Phillips’ religious-freedom claim raises endless line-drawing questions, so his free-speech argument is an opening to a new wave of litigation challenging basic elements of commercial law. Most of those cases will lose, but a question that should be on the justices’ minds is whether the uncertainty and endless litigation will be worth the candle.

Aziz Huq is the Frank and Bernice J. Greenberg Professor of Law at the University of Chicago Law School.