As a general rule, the First Amendment guaranty of religious freedom only provides protection against government acts purposely designed to inhibit or require the expression of religious faith. If the government mandates school prayer, that's a problem. If the government bans certain religious symbols from being publicly displayed on private property, that's a problem. On the other hand, general laws that happen to inhibit religious practices are usually untouched by the First Amendment. Thus, for example, laws that ban serving alcohol to minors aren't unconstitutional even though they might inhibit Catholic priests from giving communion wine to young parishioners (as a practical matter, most state alcohol laws contain exemptions for priests serving alcohol as part of a religious ceremony, but that's an exception in the law, not in the Constitution). The only time a general law runs afoul of the First Amendment is if it's really a stealth attack on religion. Thus, a law that bans all headwear, then contains a list of exemptions that removes every conceivable piece of headware from the ban except yarmulkes would be unconstitutional despite being couched in religion-neutral language. Other than that, there's no way you can use your religion to get out of obeying a general law.
Unless you're Amish.
This is the legacy of Wisconsin v. Yoder, one of the Supreme Court's most embarrassing bits of caselaw. The case came to the court in 1972 and concerned a small Old-Order Amish community in Wisconsin. Wisconsin had a law requiring children to be educated, whether in public or private schools, until 16 years old. Several members of the Menonite community in question withdrew their children after the 8th Grade, when they were 13 or 14 years old, claiming that their beliefs forbade obtaining education beyond the basics learned in elementary and middle school. The state brought them to court over the issue.
The law hadn't yet developed to the point it has now, but there were still enough decisions on the intersection of religion and education to state that, broadly, you could not use religion as a reason to opt out of the educational system entirely. Wisconsin thought it had an open-and-shut case. And it did. A young prosecutor was given the case and he presented hardly no witnesses and did barely any cross examination. The defense relied upon an expert witness, Professor John Hostetler, an anthropologist who specialized in studyin the Amish communities in the United States.
Hostetler presented an idyllic picture of Amish life. A simple folk, the Amish live isolated lives that forbid the use of even simple technologies that we take for granted. Among their beliefs is that one should not think to highly of oneself or concern oneself with matters beyond one's calling. Thus, the education in science, history, and higher mathematics required by Wisconsin's high school curriculum interfered with the practice of their religion. Even high school education within Amish schoolhouses was too much; Amish children reached the threshold of necessary knowledge at the end of the 8th grade, and beyond that further learning was offensive. Education up until then was fine; children needed to know how to read in order to know their bibles, to write and to do simple arithmetic in order to conduct the business of the farm. Anything more advanced, however, was forbidden.
He also touched, particularly in cross-examination, on another problem with high school education. As students progress in the school system they begin learning value systems that are at variance with the Amish culture. High schools teach love of technology and modern society. They teach the values of competition and individual achievement, while the Amish prioritize the community over the individual. All of these are, perhaps, persuasive arguments for a law-maker. But the Constitution has nothing to say about them. There is no constitutional protection of the integrity of your community, only of your right to individual religious expression. Hostetler tried, as much as he could, to tie the communitarian argument in with the religious one; insofar as Amish religion is heavily focused on the community, preservation of the Amish culture and protection of their religious believs were one and the same.
There's something else in Hostetler's testimony, only briefly hinted at. The Amish community at the time was facing a huge problem with abandonment by its children. Population growth among the Old-Order Amish had become stagnant, because many Amish youths were leaving the community once they were old enough to set out on their own. One of the reasons the Amish community wanted to stop sending their children to high school was to make it harder for them to leave the community by giving them fewer of the skills necessary to survive in modern society.
Not surprisingly, the court ruled against the Amish. The arguments about religion were nice, but didn't really fall within the scope of the First Amendment. Yoder lost again on appeal. But then the Wisconsin Supreme Court, somewhat bafflingly, reversed the lower court and ruled in favor of the Yoders. The state appealed, and the Supreme Court took the case.
The Court ruled for the Yoders. In a decision that constitutional scholars still find embarrassing, the 7-justice majority found that the Amish had a right to withdraw their children from high school for religious reasons. The opinion is a paean to the glories of the simple, rural lives that the Amish lead. The majority offers very little basis for their decision other than "who are we to interfere with their way of life?" If they decide that they want to reject modern society and withdraw from the educational system, who are we to stop them?
The lone dissenter, Justice William O. Douglas, calls into question exactly whose decision the majority is respecting, that of the parents or of the children. Our Constitution has an individual-orientation, not a community-orientation. We preserve individual rights, not community ones. If a law interferes with the right of a community to decide the fate of its children, that interference has precisely nothing to do with the Constitution. In America, we have decided that, to ensure individual ample opportunities throughout thei lives, everyone must be educated through a certain age. Even if that education interferes with certain values that a community may hold, it should not be made optional. We ought not, he argued, sacrifice individual rights to preserve insular communities.
Justice Douglas was not persuasive enough, and to this day First Amendment law contains a dubious exception for the Amish when it comes to education, an exception not granted to any other religious group. Others have tried. They have all failed. Only the Amish receive this exemption from general laws.
Since Yoder, the Amish have universally withdrawn their children from high school. Within a few years, abandonment of the community by Amish youths had dropped to nearly nothing.
What's interesting is how much of the decision in Yoder turned on Hostetler's testimony. Wisconsin figured it had an easy case, so they prepared only a weak case at trial. As such, the only factual basis regarding the Amish community was provided by Hostetler, and his cross-examination by the state was short and perfunctory. The problem is that in the American system finding facts is the function of the trial court, not appellate courts; once the trial ended, Hostetler's testimony was the only testimony the Supreme Court could look at. And, as you might imagine, Hostetler's testimony was glowingly positive for the Amish case.
The problem is that Hostetler had very good reasons for wanting to see the Amish community preserved. He was an anthropologist who had built his career on studying the Amish. The Amish community was stagnant and education was part of what was causing its population problems. Of course he was willing to say what was necessary to preserve his niche, the people he made a career out of studying. Hostetler didn't necessarily lie on the stand, but he did fudge some things and elide certain facts to present a more friendly picture than was reality. When an expert witness's livelihood depends on the court ruling one direction, the Court ought to grant that witness's testimony less credibility than it did in this case.
What's interesting about Yoder is the degree to which the outcome turned on one expert's testimony. Given the realities of the tendency for experts to become entranced by their subjects, the Court would have been well served to treat the anthropologist's testimony a bit more skeptically than it did.