What do you mean by "regulate?" What I take it to mean, is the authorization of law enforcement /government to variously penalize people, through force, coercion, arrest, imprisonment, etc., according to whether said people are innocent /law abiding, or criminals. So the law is that authorization. The law "releases the hounds" so to speak, licitly and validly, not criminally, such as in true cases of police brutality. So that's what I think when you say "regulate," and so my view is that the right to religious liberty is inalienable, and so no law can validly and licitly authorize law enforcement /government to harass, etc. people in any matter of faith or morals. And so I think that ideally (we are not ideal right now in the US, although we are at the top of the heap), laws are made only that authorize law enforcement /government to trouble people who infringe the inalienable rights of others.
But what do you mean by "regulate?"