All jurisdictions in the US require proof of vaccination for school entrance. Most states permit non-medical exemptions. Public health officials must balance the rights of individuals to choose whether or not to vaccinate their children with the individual and societal risks associated with choosing not to vaccinate (i.e., claiming an exemption). To assist the public health community in optimally reaching this balance, this analysis examines the constitutional basis of non-medical exemptions and examines policies governing conscientious objection to conscription as a possible model. The jurisprudence that the US Supreme Court has developed in cases in which religious beliefs conflict with public or state interests suggests that mandatory immunization against dangerous diseases does not violate the First Amendment right to free exercise of religion. Accordingly, states do not have a constitutional obligation to enact religious exemptions. Applying the model of conscientious objectors to conscription suggests that if states choose to offer nonmedical exemptions, they may be able to optimally balance individual freedoms with public good by considering the sincerity of beliefs and requiring parents considering exemptions to attend individual educational counseling.