David French warns National Review Online readers that partisan hatred threatens cherished constitutional freedoms.

In more than two decades of advocacy for free speech, I’ve learned that it’s easy to persuade Americans to respect the civil liberties of people they disagree with. It’s much, much more difficult to persuade the same Americans to respect the rights of those they loathe. Demonize the opposition enough and eventually your tribe will get busy finding ways to rationalize and justify blatant censorship and double standards.

The Bill of Rights was designed to be counter-majoritarian. As the saying goes, our civil liberties aren’t up for a vote. And this is true . . . in the short and medium terms. Over the long term, however, civil liberties — just like politics — follow the culture. And when the political culture is driven by a spirit of vengeance, only the complacent believe that our fundamental freedoms will remain intact.

Consider the fact that the Supreme Court is even now pondering two key compelled-speech cases concerning the attempts of progressives in Colorado and California to force people of faith to violate their consciences. In Colorado, the state is attempting to conscript a Christian baker into using his artistic talents to help celebrate a same-sex union he believes is unholy. In California, the state is trying to force pro-life crisis-pregnancy centers to advertise for free or low-cost abortions. An adverse ruling in either case would do damage to decades of free-speech jurisprudence. But I fear that positive rulings may only stem the tide for a time.

Continue down the present path, and legislators will keep passing laws designed to suppress opposing views.