The conversation about a cake lasted less than a minute but will long reverberate in constitutional law. On Tuesday, the Supreme Court is scheduled to hear 60 minutes of speech about when, if at all, making a cake counts as constitutionally protected speech and, if so, what the implications are for the Colorado Civil Rights Commission’s contention that Jack Phillips violated the state’s law against sexual-orientation discrimination.

Phillips, 61, is a devout Christian and proprietor of Masterpiece Cakeshop in Lakewood, CO, where he works as — his description — a cake artist. Charlie Craig and David Mullins entered his shop to order a cake to celebrate their wedding. Phillips said that although he would gladly make cakes for gay people for birthdays or other celebrations, he disapproves of same-sex marriage on religious grounds, and so does not make cakes for such celebrations. (He also refuses, for religious reasons, to make Halloween cakes.) To be compelled to do so would, he says, violate his constitutional right to speak freely. This, he says, includes the right not to be compelled to contribute his expressive cake artistry to a ceremony or occasion celebrating ideas or practices he does not condone. Well.

The First Amendment speaks of speech; its presence in a political document establishes its core purpose as the protection of speech intended for public persuasion. The amendment has, however, been rightly construed broadly to protect many expressive activities. Many, but there must be limits.

Phillips was neither asked nor required to attend, let alone participate in, the wedding. Same-sex marriage was not yet legal in Colorado, so Craig and Mullins were to be married in Massachusetts. The cake was for a subsequent reception in Denver. But even if the cake were to have been consumed at a wedding, Phillips’ creation of the cake before the ceremony would not have constituted participation in any meaningful sense.

Six decades ago, the civil rights movement gained momentum through heroic acts of civil disobedience by African-Americans whose sit-ins at lunch counters, and other challenges to segregation in commerce, produced the “public accommodations” section of the 1964 Civil Rights Act. It established the principle that those who open their doors for business must serve all who enter. That principle would become quite porous were it suspended whenever someone claimed his or her conduct was speech expressing an idea, and therefore created a constitutional exemption from a valid and neutral law of general applicability.

Photography is inherently a creative, expressive art, so photographers have a strong case against compulsory documentation of ceremonies at which they must be present. Less clearly but plausibly, florists can claim aesthetic expression in floral arrangements, but their work is done before wedding ceremonies occur. Chauffeurs facilitate ceremonies, but First Amendment jurisprudence would become incoherent if it protected unwilling chauffeurs from their supposedly expressive participation in ceremonies to which they deliver actual participants.

It is difficult to formulate a limiting principle that draws a bright line distinguishing essentially expressive conduct from conduct with incidental or negligible expressive possibilities. Nevertheless, it can be easy to identify some things that clearly are on one side of the line or the other. So, regarding Phillips’ creations:

A cake can be a medium for creativity; hence, in some not-too-expansive sense, it can be food for thought. However, it certainly, and primarily, is food. And the creator’s involvement with it ends when he sends it away to those who consume it. Phillips ought to lose this case. But Craig and Mullins, who sought his punishment, have behaved abominably.

To make his vocation compatible with his convictions and Colorado law Phillips has stopped making wedding cakes, which was his principal pleasure and 40 percent of his business. He now has only four employees, down from 10. Craig and Mullins, who have caused him serious financial loss and emotional distress, might be feeling virtuous for having done so. But siccing the government on him was nasty.

Denver has many bakers who, not having Phillips’ scruples, would have unhesitatingly supplied the cake they desired. So, it was not necessary for Craig’s and Mullins’ satisfaction as consumers to submit Phillips to government coercion. Evidently, however, it was necessary for their satisfaction as asserters of their rights as a same-sex couple.

Phillips’ obedience to his religious convictions neither expressed animus toward them nor injured them nor seriously inconvenienced them. Their side’s sweeping victory in the struggle over gay rights has been decisive, and now less bullying and more magnanimity from the victors would be seemly.

© 2017, Washington Post Writers Group