The Bill of Rights of the U.S. Constitution includes numerous civil rights and liberties afforded to all U.S. citizens, such as freedom of speech and religion. Before the Civil War, however, these were only valid at the federal level, restricting the power of the national government but not that of the state governments. Incorporation theory describes how the U.S. Supreme Court has gradually extended these privileges to limit state power as well.
The 14th Amendment
Before the Civil War, there was no legal basis for extending the Bill of Rights to the state level. In Barron v. Baltimore (1833), Chief Justice John Marshall argued that the Bill of Rights only restricted the federal government, and that state constitutions alone limited state power. In 1868, however, Congress passed the 14th Amendment, which checked state power through the due process and privileges and immunities clauses. The U.S. Supreme Court would be responsible for interpreting the scope of these restraints on state power.
The Slaughterhouse Cases
The Supreme Court first addressed the 14th Amendment’s limitations on state power in The Slaughterhouse Cases (1873). In these cases, a group of butchers argued that a slaughterhouse company’s attempt to create a monopoly in New Orleans violated the 14th Amendment’s privileges and immunities clause. In its opinion, the court narrowly interpreted the 14th Amendment, declaring that it only concerned citizen rights for slaves. It appeared that the 14th Amendment would not be the vehicle for applying the Bill of Rights to the states at this time.
In the early 20th century, however, the Supreme Court’s opinion on the 14th Amendment would shift. In Gitlow v. New York (1925), the court argued that the freedoms of speech and press were extended to the states by the due process clause of the 14th Amendment. Through this and several other cases, the court began the process of selective incorporation, in which the amendments of the Bill of Rights would be applied to the states on a case-by-case basis. This doctrine is in contrast with that of total incorporation, which says that the entirety of the Bill of Rights should be incorporated to the states. In Palko v. Connecticut (1937), the court specifically rejected the doctrine of total incorporation in favor of selective incorporation.
The Warren Court
In 1953, President Eisenhower nominated Earl Warren to be chief justice of the Supreme Court. The impact of the Warren Court, which lasted until 1969, would be groundbreaking. Through a number of cases, the Warren Court would almost completely incorporate the first eight constitutional amendments. Some of these cases included Engel v. Vitale (1962), which incorporated freedom of religion, as well as Mapp v. Ohio (1961), Gideon v. Wainwright (1963) and Miranda v. Arizona (1966), which incorporated several rights of accused criminals contained in the Fourth, Fifth and Sixth Amendments. With the Bill of Rights almost completely incorporated, state power was now more limited than ever.