A reminder of why we would want to protect religious liberty:
Certainly, mankind without Christianity conjures up a dismal prospect. The record of mankind with Christianity is daunting enough…. The dynamism it has unleashed has brought massacre and torture, intolerance and destructive pride on a huge scale, for there is a cruel and pitiless nature in man which is sometimes impervious to Christian restraints and encouragements. But without these restraints, bereft of these encouragements, how much more horrific the history of these last 2,000 years must have been! … In the last generation, with public Christianity in headlong retreat, we have caught our first, distant view of a de-Christianized world, and it is not encouraging.
Paul Johnson, History of Christianity