The Fourteenth Amendment was adopted in 1868 after the Civil War. In 1879, the Supreme Court observed that the Thirteenth and Fourteenth Amendments were adopted “to raise the colored race from that condition of inferiority and servitude in which most of them had previously stood, into perfect equality of civil rights with all other persons within the jurisdiction of the States.” The Fourteenth Amendment reads in relevant part: “nor shall any State deprive any person of life, liberty, or property, without due process of law.”
After the adoption of the Fourteenth Amendment, the Court’s jurisprudence on religion did not change in three important respects. First, the Court did not appear to think that the Fourteenth Amendment prohibited the States from establishing a religion.
Second, the Court continued to define religion as Madison defined it, and as it was defined in dictionaries written around the founding of the country. The Court defined religion to refer to “one's views of his [relationship] to his Creator, and to the obligations they impose of reverence for his being and character, and of obedience to his will.” The Court said that the term ‘religion’ is often confused with “the cultus or form of worship of a particular sect” when they are not the same thing.
Third, the Court continued to recognize that freedom of religion is subordinate to the law, and the law is founded upon the values and beliefs of the Christian religion. The exercise of religion is subordinate to “the criminal laws of the country, passed with reference to actions regarded by general consent as properly the subjects of punitive [legislation].” It has never been seriously argued that ‘freedom of religion’ means that “the whole punitive power of the government for acts, recognized by the general consent of the Christian world in modern times as proper matters for prohibitory legislation, must be suspended in order that the tenets of a religious sect encouraging crime may be carried out without hindrance.”
In the 1878 case of Reynolds v. U.S., the Court rejected the argument of a Mormon convicted of the crime of bigamy that the Constitution protected him because of his religious beliefs. At the time, polygamy was mandatory on male members of the Church of Jesus Christ of Latter-Day Saints under penalty of damnation in the life to come if the individual failed to or refused. The court argued that marriage is a critical foundation of society which can be regulated by law. If people could exempt themselves from the law because of their religious beliefs, it would put their religious beliefs above the law. Suppose someone believed that “human sacrifices were a necessary part of religious worship,” or a “wife religiously believed it was her duty to burn herself upon the funeral pile of her dead husband.” It would not be seriously argued that civil government could not interfere and prevent this from happening.
Twelve years later, the Court upheld laws requiring an oath that the person does not believe in polygamy and is not a member of an organization that is, as part of the voting registration process. The Court noted that the constitutions of thirteen states expressly limit religious freedom so as “not to be construed to excuse acts of licentiousness, or to justify practices inconsistent with the peace and safety of the state.”
In Rector v. U.S., the Court presented extensive evidence to support the proposition that the underlying common law of the country is religious and Christian. The Court said: "If we examine the constitutions of the various states, we find in them a constant recognition of religious obligations. Every constitution of every one of the 44 states contains language which, either directly or by clear implication, recognizes a profound reverence for religion, and an assumption that its influence in all human affairs is essential to the well-being of the community.”
The Court provided several examples including the constitution of Delaware, which requires a belief in the Trinity to hold a public office, the constitution of Mississippi which required a belief in God and a future state of rewards and punishments, and the constitution of Massachusetts which authorized the legislature to “authorize and require” suitable provision for the “institution of the public worship of God and for the support and maintenance of public Protestant teachers of piety, religion, and morality.”
The Court said that there was no disconnect between these declarations and the Constitution of the United States. These, and many other examples “add a volume of unofficial declarations to the mass of organic utterances that this is a Christian nation.” The Court quoted the Supreme Court of Pennsylvania, which explained that by “Christian,” it meant “not Christianity with an established church and tithes and spiritual courts, but Christianity with liberty of conscience to all men” It also quoted the Supreme Court of New York, saying that it is an abuse of the freedom to discuss religious opinions to “revile, with malicious and blasphemous contempt” the religion of Christianity. In addition, the Constitution does not place the “strange” requirement that the state punish similar attacks against “[Islam] or of the Grand Lama; and for this plain reason, that the case assumes that we are a Christian people.”
The only substantive change in the Constitution’s approach to religion after the passage of the Fourteenth Amendment was that it imposed some minimal limitations on State action that did not exist before. The Court said:
"While this court has not attempted to define with exactness the liberty [protected by the Fourteenth Amendment,] … Without doubt, it denotes not merely freedom from bodily restraint but also the right of the individual to … worship God according to the dictates of his own conscience, and generally to enjoy those privileges long recognized at common law as essential to the orderly pursuit of happiness by free men…. The established doctrine is that this liberty may not be interfered with, under the guise of protecting the public interest, by legislative action which is arbitrary or without reasonable relation to some purpose within the competency of the state to effect."
So the States were still free to manage their respective social fabric. However, the federal government would act as a safety mechanism to protect minorities in the States from the injustice of excessively arbitrary or irrational laws.