The Masterpiece Cakeshop case argued Tuesday before the Supreme Court cuts to the core of who we are as a country. I’ve teamed up with Freedom for All Americans, a bipartisan campaign dedicated to ensuring every American is fully protected from discrimination under the law, to help people understand its potential impact.

I don’t know Colorado baker Jack Phillips, so I have no basis to speculate on the sincerity of the religious beliefs he says would be violated if he had to make a wedding cake for a gay couple. What I do know is that I grew up under Jim Crow. I know that we, as a nation, have seen arguments like his before.

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It wasn’t long ago, in our history, when politicians and business owners made similar religious liberty arguments to justify segregation in businesses. Because of that dark chapter in our history, we decided — long ago — that when a business is open to the public, that means every member of the public.

I also know that I’ve undergone my own evolution on the issue of LGBT equality. I speak often about my journey, most recently at a brunch hosted by the American Unity Fund at last year’s Republican Convention. In my talk, I admitted that I’m not proud that during my career as a naval Intelligence officer, I processed worthy service members out of the military for being gay. My heart has changed, due in large part to patient counsel by friends in the LGBT community who helped me understand why I was wrong. When I reflect on my beliefs back then, I’m struck by the depth of my ignorance. I’m also reminded that I can’t be silent on this issue, because inequality for some jeopardizes freedom for all.

Governing a free country requires a balancing act of competing rights. Religious people in this country are entitled to near absolute protection of their beliefs, and rightfully so. Every house of worship has the right to define for whom they provide sacraments, whether it’s the sacrament of baptism, or religious marriage. Religious people, however, are not entitled to absolute protection of their actions. When a business owner refuses service to customers based on their sexual identity, that isn’t religious liberty. It’s discrimination.

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If our history has taught us anything, it’s that second-class citizenship is unacceptable. Yet Phillips, an evangelical Christian who owns Masterpiece Cakeshop, is arguing in favor of just that for LGBT Americans. He is asking the court to give him — and those who think like him — a license to discriminate against LGBT individuals. In this case, there has been absolutely no affront to Phillips’ religious liberty. He was and remains free to attend the church of his choosing and worship however he pleases.

Phillips has chosen Alliance Defending Freedom (ADF) to help him challenge the Colorado anti-discrimination law he is accused of violating. This troubles me because ADF has a history of animosity toward LGBT Americans. In 2002, for example,when it was still called Alliance Defense Fund, the organization filed a brief urging the Supreme Court to uphold a Texas law making homosexual activity illegal.

Furthermore, much of ADF’s international work involves trying to make being LGBT illegal. In the run up to the Olympics, ADF published a nine-page memo defending a Russian law that targeted LGBT people in the name of “protecting children.” ADF, it seems to me, is using the legal process to bully and demean LGBT people wherever and whenever possible. Philips’ association with ADF contradicts his insistence that this case is not motivated by discrimination.

Businesses open to the public must be open to everyone on the same terms. That’s not a novel concept. It’s ripped from the playbook of civil rights warriors like Dr. Martin Luther King. Back in his time, many justified segregation by hiding behind a poorly-defined concept of “religious liberty.” They were wrong then, and Phillips and ADF are wrong now. There is no religious license to discriminate now; and I pray the Supreme Court’s decision ensures there will never be.

Montel Williams, a 22-year veteran of the Marine Corps and Navy who served primarily as a special duty intelligence officer, went on to start the Emmy-award-winning Montel Williams Show that ran for 17 seasons. Follow him on Twitter: @Montel_Williams.

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