Here are a list of precedents for the case.
Thomas v. Review Board of Indiana (1981): The Court ruled that religious beliefs need not be acceptable, logical, consistent, or comprehensible to others in order to merit First Amendment protection.
Employment Division of Oregon v. Smith (1990): A Law that burdens religious practice need not be justified by a compelling governmental interest if it is neutral and of general applicability.
Frazee v. Illinois (1989): The assertion that animal sacrifice is an integral part of (Santerian) religion cannot be deemed bizarre or incredible.
McGowan v. Maryland (1961): A social harm may have been a legitimate concern of government for reasons quite apart from discrimination.
Schneider v. State of New Jersey (1939): The neutrality of a law is suspect if First Amendment freedoms are curtailed ot prevent isolated collateral harms not themselves prohibited by direct regulation.