Perhaps the most significant religion case in the 19th century was Reynolds v. United States (1878), in which the Court was called upon to weigh the religious commandments of a relatively new sect, the Mormons. The case involved the crime of bigamy—entering into more than one marriage at the same time—which an 1862 law prohibited in the territories. The question raised by the defendant was: “Should the accused have been acquitted if he married the second time, because he believed it to be his religious duty?”
Chief Justice Waite, who wrote the opinion of the Supreme Court, quoted Jefferson’s letter to the Danbury Baptists. Not only did he quote the portion about “building a wall of separation between church and State,” he also included the part in which Jefferson states his conviction that man “has no natural right in opposition to his social duties.” While the Court acknowledged that “Congress was deprived of all legislative power over mere opinion,” it decided that it “was left free to reach actions which were in violation of social duties or subversive of good order.” In the Reynolds case, the Court concluded that the 1862 law against bigamy in the Territories “was done because of the evil consequences that were supposed to flow from plural marriages.” Therefore, the court concluded that the argument of social order was sufficiently compelling to trump what the defendant had asserted was a divine commandment, and no religious exclusions to the law against bigamy were allowed.