A brief discussion about a wedding cake has grown into a U.S. Supreme Court collision of some of the nation’s most cherished values.

In a dispute that pits free speech and religious rights against equality, the justices on Tuesday will consider the case of a Colorado baker who refuses to make cakes for same-sex weddings.

The hour-long argument will mark the first full-scale test of gay rights since the court legalized same-sex marriage nationwide in 2015. For supporters, the case threatens to undercut the “equal dignity” the court promised same-sex couples in that decision.

“This is about us being denied service at a public business because of who we are and who we love,” said David Mullins, who triggered the legal fight when he and his husband, Charlie Craig, visited Masterpiece Cakeshop in 2012.

For bakery owner Jack Phillips, the case is about something very different. He says Colorado officials are trying to coerce him into creating a work of art to celebrate an event he believes is forbidden by the Bible. He is pressing free-speech and religious-rights arguments in fighting an order that requires him to either make wedding cakes for gay couples or not make them at all.

“The law is trying to force me to violate my faith,” Phillips said.

Florists, Photographers

The case will have its most direct impact on the 22 states that bar discrimination on the basis of sexual orientation by establishments that do business with the public. Lower courts in some of those states have ruled that florists, photographers and building owners must provide the same services for gay weddings as for opposite-sex ceremonies.

More broadly, the case calls on the justices to take sides on a defining issue in the nation’s culture wars. In a testament to the wide public interest in the case, the line to claim one of the public seats for the session started forming Friday, and by Monday morning several dozen people were camped out on the court’s front sidewalk.

The court has received more than 90 outside briefs. A group of businesses, including Apple Inc. and Amazon.com Inc., is backing the couple, while the Trump administration supports Phillips.

The key to Supreme Court fight, as is so often the case, will be Justice Anthony Kennedy, who is the author of the court’s four most important gay-rights rulings as well as one of its foremost champions of speech rights.

“He’s a big advocate of free speech. He’s also a huge advocate of same-sex marriage and gay rights,” said Jonathan Turley, a constitutional law professor at George Washington University Law School.

Short Conversation

The dispute began before gay marriage was even legal in Colorado. Mullins and Craig were planning to wed in Massachusetts and then hold a wedding reception in Colorado. Their reception site referred them to Masterpiece for the cake.

Almost as soon as they sat down in the bakery on that July day, Phillips told them he wouldn’t make what they wanted.

“I said, ‘I’ll make you birthday cakes, shower cakes, sell you brownies, cookies, anything else. I just don’t do cakes for same-sex weddings,’” Phillips said, amid the cookies and sheet cakes on display in his strip-mall shop in the Denver suburb of Lakewood.

Craig said the two men, who had brought along Mullins’s mother, were caught completely off guard.

“We were asking for a cake,” said Craig in an interview in their Denver home. “We weren’t asking for a priest to marry us.”

Civil Rights Complaint

The couple filed a civil rights complaint. State officials joined the case against Phillips, and a Colorado appeals court ruled against the bakery. The state court said Phillips wouldn’t be conveying support for same-sex marriage simply by decorating and selling wedding cakes on a non-discriminatory basis.

Phillips’s lawyers say that analysis doesn’t give enough weight to the creativity and expression that goes into each of his cakes.

“Much like an artist sketching on canvas or a sculptor using clay, Phillips meticulously crafts each wedding cake through hours of sketching, sculpting, and hand-painting,” his lawyers at the advocacy group Alliance Defending Freedom argued in court papers. The cake “announces through Phillips’s voice that a marriage has occurred and should be celebrated.”

Phillips’s team points to a unanimous 1995 Supreme Court decision that said a Boston veterans’ group had a First Amendment right not to open its St. Patrick’s Day parade to an Irish-American gay-rights organization.

Bar Mitzvahs

Lawyers at the American Civil Liberties Union, representing Craig and Mullins, say the Supreme Court has consistently ruled that businesses don’t have a constitutional right to discriminate.

The men’s lawyers say a ruling for Phillips would let bakeries refuse to make cakes for a bar mitzvah, an interracial couple’s wedding or a woman’s business school graduation party.

“There is no doubt that the bakery owner’s religious objections are sincere, but granting such a religious-based exemption would allow every business owner ‘to become a law unto himself,’” the legal team argued in court papers, quoting from an 1878 case. The Colorado Civil Rights Commission will also be arguing on the side of the two men.

Although Phillips is also making a religious-rights claim, many legal experts say they expect free speech to be the focus of the argument.

‘Inherently Expressive’

That’s in part because of a Trump administration brief that urges a limited free-speech ruling in favor of Phillips. The administration says the First Amendment protects bakers, musicians, photographers and other wedding vendors who make “inherently expressive products,” letting them decline to create custom products for same-sex weddings.

The administration says other types of wedding vendors — including hotels, banquet halls and limousine services — can be required to comply with anti-discrimination laws.

The administration “came up with a pretty narrow rule,” said Jeffrey Rosen, president of the National Constitution Center in Philadelphia. “It seems uniquely well-tailored to persuade Justice Kennedy that he can rule for the First Amendment here without calling broader anti-discrimination laws into question.”

At the same time, “he will be skeptical of any rule or law that calls the equality and dignity of gays and lesbians into question,” Rosen said. “It could well be a very hard case of the kind he agonizes about.”

The case, which the court will decide by June, is Masterpiece Cakeshop v. Colorado Civil Rights Commission, 16-111.