[1.] The Supreme Court has been debating the meaning of the Free Exercise Clause for over 60 years. One view has been that the Clause generally gives religious objectors a presumptive right to be exempted from generally applicable laws, such as from bans on using peyote, requirements that one provide one's child's social security number to get various welfare benefits, requirements to provide certain health insurance to one's employees, and anything else that might conflict with one's religious beliefs.
This right was just a presumption, which the government could rebut if it has a strong enough reason. And indeed the presumption was often found to have been rebutted, in cases involving draft laws, tax laws, antidiscrimination laws, child labor laws, and more. But the presumption, though not very strong, was broad: It applied to a wide range of religious practices. Historically, that view had been associated mostly with the liberals on the Court, such as Justices Brennan and Marshall. The leading precedent here was Sherbert v. Verner (1963), written by Justice Brennan.
The opposite view has been that the Clause only forbids discrimination targeting religious believers or practices (such as laws that ban religious animal sacrifice but allow virtually identical secular killing of animals, or laws that exclude religious schools from various benefit programs that are offered to secular private schools). Historically, that view had been associated mostly with the conservatives on the Court, such as Justice Scalia and Chief Justice Rehnquist. The leading precedent here was Employment Division v. Smith (1990), written by Justice Scalia.
