The present doctrinal development begins with Church of Lukumi Babalu Aye v. Hialeah (1993), in which the Court invalidated a ban on animal sacrifice. The Court had previously held that there was no right to religious exemptions from neutral laws. But this law wasn't neutral. It targeted an unpopular religion of Caribbean immigrants. The laws, the Court concluded, were "drafted with care to forbid few killings but those occasioned by animal sacrifice." The state said that it had a legitimate interest in preventing cruelty to animals. The Court retorted that the city "devalues religious reasons for killing by judging them to be of lesser import than nonreligious reasons."
In Hialeah, animals could be killed, sometimes painfully, for all sorts of nonreligious reasons. Live rabbits were used to train greyhounds. The city's laws, the Court said, "fail to prohibit nonreligious conduct that endangers these interests in a similar or greater degree than Santeria sacrifice does." That showed an impermissible purpose. "The record in this case compels the conclusion that suppression of the central element of the Santeria worship service was the object of [Hialeah's] ordinances."
The claim in Lukumi built on language in Smith distinguishing earlier cases in which it had overturned state refusals of unemployment benefit to claimants who refused work for religious reasons. Where there is "a system of 'individualized governmental assessment of the reasons for the relevant conduct,'" the Smith court had declared, government "'may not refuse to extend that system to cases of 'religious hardship' without compelling reason.'" When Justice Scalia wrote that, he probably did not intend to lay down a sweeping new rule. Michael McConnell is right that this language had "one function only: to enable the Court to reach the conclusion it desired in Smith without openly overruling any prior decisions."
