In oral arguments before the U.S. Supreme Court late last year, the justices struggled mightily in an important case to reconcile two very weighty and competing interests: a baker's right to adhere to his religious beliefs in declining to design a custom wedding cake for a gay couple and that couple's right not to be discriminated against and demeaned in the marketplace.

The baker's main argument is grounded in a World War II-era decision where Justice Robert Jackson masterfully explained why Jehovah's Witness school children could not be compelled to salute the flag and say the pledge of allegiance contrary to their religious beliefs. “If there is any fixed star in our constitutional constellation,” Jackson wrote, “it is that no official, high or petty, can prescribe what shall be orthodox in politics, nationalism, religion, or other matters of opinion or force citizens to confess by word or act their faith therein.” Hence was born the principle of freedom of belief, and the government's inability to compel people to express themselves contrary to their beliefs. Jackson could have rested the decision on narrower grounds of free exercise of religion, but instead opted to recognize a general free speech right against compelled expression.

Understandably, the baker is arguing that the application of Colorado's anti-discrimination law to him is coercing him to express himself artistically in the service of a cause that violates his religious beliefs. His lawyer analogized it to forcing a black sculptor to design a cross for a Ku Klux Klan rally.

While there is merit in the baker's position, the court should not follow Jackson's compelled-speech path in this case. Instead, it should decide it on the narrower grounds of free exercise of religion. Why? Recognizing a right of providers to not serve someone in the marketplace based on their general beliefs would unnecessarily open up a can of worms.

First, how does the court define what sort of goods or services are made with sufficient expression to warrant free speech protection? The line-drawing problems are daunting. As various justices suggested at argument, could a chef who makes fancy designs on her white chocolate truffles refuse service?

More troubling, would any belief merit protection? What about a firmly held belief that a particular race was not worthy of one's artistic efforts? A decision upholding the baker's claim on general freedom of belief grounds could create a license to discriminate against anyone a provider disliked.

So why would a free exercise of religion decision be a preferable way to balance the competing interests in this case? First, allowing a provider with sincere religious objections to decline to provide an expressive product or service would narrow substantially the potential field of conflict (and circumstances under which same-sex couples could be denied service).

Second, the court already has precedent to support such a path that is not only anchored in two of the most fundamental rights in our Constitution (freedom of speech and religion), but recognizes that same-sex couples cannot be refused service if there are no alternative providers reasonably available to meet their needs. Lastly, the court also has precedent that permits the subtle policing by courts of “fringe” religious beliefs being asserted as a pretext to permit rank discrimination.

In a 1990 decision written by the late Justice Antonin Scalia for a deeply divided court, it reversed years of precedent and held that if a law was not designed to hinder religious beliefs or practices—such as the Colorado nondiscrimination law—then individuals could not refuse compliance with it on the grounds of religion (before that, the court had held the government to a demanding standard of need to deny a religious exemption to a secular law). Scalia's main rationale for reversing course was that it was too difficult for judges to balance the public's need for a secular law against an individual's religious needs. That was mainly the job of legislatures should they choose to voluntarily include religious exemptions in secular laws.

Scalia, however, strongly suggested that if a religious objection to compliance with a law also combined other constitutional rights such as free speech (a so-called hybrid right), then the government would still need to show there was no alternative way to satisfy its goals other than infringing on the free speech and religion rights.

The baker's case presents a classic instance of a hybrid right combining coerced expression linked to religious beliefs. Under Scalia's paradigm, the baker should be allowed to decline service so long as the same-sex couple can find other bakers to custom design their cake—not a difficult feat in Denver. Alternatively, if same-sex couples lived in sparsely populated areas with one custom-designing baker, for instance, then the baker would need to serve them or just sell off-the-shelf cakes to anyone (or perhaps affiliate with a custom-designing baker out of the area who did not have religious objections).

Moreover, the court has made it clear that for religious freedom protections to kick in a belief must be religious, ethical or moral in nature, as opposed to being exclusively political, sociological or philosophical. And it has said that while courts have no business inquiring into the legitimacy of a religious belief, they may inquire into the sincerity with which it is held. In practice, lower courts use this distinction to deny protection to purported religious beliefs that appear to mask hidden agendas, such as a desire not to pay taxes or, more relevant to this case, a desire to be a mere racist or other bigot.

A hybrid rights paradigm is not a perfect solution. It would still require courts to decide when a marketplace provider's act became sufficiently expressive for free speech protection to apply. But this has been something courts have been doing for years in other areas, and in the marketplace context, a hybrid rights scheme would cause the issue to arise much less often.

In short, a decision based on freedom of religion principles would be a better way to accommodate the competing interests in this case than broader compelled speech grounds (or simply forcing the baker to a Hobson's choice of designing against his will or not designing at all. And since both free speech and religion rights have been asserted by the baker, the court should simply remove free speech from the driver's seat and make free religion the focus of its attention.

Barry P. McDonald is a professor of constitutional law at Pepperdine University, and served as a law clerk for the late Supreme Court Chief Justice William H. Rehnquist.