When Charlie Craig and David Mullins swung open the door to Jack Phillips’ bakery on a summer day in 2012, they were just going to see a man about a cake.

Now all three of them are going to the Supreme Court — because, as it turned out, Masterpiece Cakeshop doesn’t do cakes for same-sex weddings.

The five-year-old legal tussle over Phillips’ confections and the gay couple’s affections will reach its zenith next week, when lawyers for both sides as well as the state of Colorado and the United States come before the nation’s highest court to debate the expressive content of a wedding cake.

In a Supreme Court term featuring potential landmark cases on voting rights, privacy rights, workers’ rights and states’ rights, it is the justices’ third date with same-sex marriagethat’s dominating the docket. It will test the Constitution’s guarantee of free speech and religion against state laws prohibiting discrimination.

The battle has taken a financial toll on Phillips and an emotional toll on Craig and Mullins, but neither side has any regrets. Phillips is fighting for the right of “creative artists” to choose what they will sell. Craig and Mullins are fighting for the right of LGBT customers to choose what they will buy.

“I’m sure their feelings are as important to them as mine are to me,” Phillips said one recent morning, taking a break from decorating cakes to speak with a reporter.

“I want him to have his own religious beliefs and his own experiences and his own ideas,” Craig said later that day in his Denver home, surrounded by his husband, dog and cat.

Then Mullins quickly added: “But you cannot practice your religion in a way that denigrates others or excludes them from full participation in public life.”

The three men haven’t spoken since their brief altercation on July 19, 2012, but next Tuesday won’t be the first time they’ve met in court. Thus far, Craig and Mullins have won at the Colorado Civil Rights Commission and the state Court of Appeals. But the Supreme Court, bolstered in April by the addition of stalwart conservative and fellow Coloradan Neil Gorsuch, could be a different story.

In the interim, Phillips has lost an estimated 40% of his business because he’s stopped making wedding cakes altogether. A workforce that once numbered 10 is down to four, including his daughter and sister-in-law.

Mullins and Craig have endured the initial pain and humiliation of being turned away, wedding binder in hand, as well as the residual impact of being alert to other forms of discrimination.

All because of a cake. OR IS IT?