Judging from the coverage surrounding this week’s blockbuster case, Masterpiece Cakeshop v. Colorado Civil Rights Commission, it might seem that the legal clash between religious liberty and discrimination in public spaces is a modern controversy that the Supreme Court is just catching up to. But more than 50 years ago, John W. Mungin, a black Baptist minister, was threatened with deadly force and told to leave a famous South Carolina barbecue restaurant—all because its owner held to the belief that the races should be kept strictly separated.