If pornography is banned on grounds that it is harmful children, we open a door to significant new state restrictions on content in the future. There are already plenty who argue that teaching religion to young children is harmful, that it’s a morally untenable “indoctrination” which takes advantage of kids’ gullibility and the trust they place in their parents to brainwash them into religiosity before they are able to encounter and assess faith as rational adults. Researchers at Boston University reported in 2014 that “young children with a religious background are less able to distinguish between fantasy and reality compared with their secular counterparts.” Richard Dawkins says teaching children religion is “child abuse.” We could even note that high teen birth rates correlate with higher rates of religiosity, a fact that can be explained by value systems which lead pregnant teens to carry their babies to term instead of aborting — but which could also be used to argue religion is objectively harmful to teenagers, who along with their children often face a host of adverse outcomes their peers are able to avoid.

If the state can ban porn because viewing it can hurt kids, it can ban other things deemed to hurt kids, too. And though bans on religious content for children now seem farfetched, let me mention two more facts. First, that religiosity is on a steep decline in America. And second, that obscenity legislation has always tended to rely on public opinion. In Miller v. California (1973), the Supreme Court established a three-pronged test for identifying obscenity, and each of the three prongs is based on the assessment of a “reasonable person” or an “average person, applying contemporary adult community standards.”