Apparently it is already happening in Canada.
Bible verses regarded as hate literature
Religious speech is not tolerated if it is considered "hateful". So much for freedom. I could see this extending to the US in the distant future. Look at the Phelps and their clan of haters. How many Americans would vote in favor of a law that would toss all of them in jail? I would bet that law would pass overwhelmingly despite the First Amendment implications. Now imagine a few generations down the road and the number of people who aren't just atheists but flat out hate all religion for whatever reason rises. What kind of laws might we see then?