The concept of selective incorporation first arose with the passage of the 14th Amendment after the Civil War. This amendment laid down important new rights of citizens, including the rights to equal protection and due process. It extended the rights outlined in the first 10 amendments to the Constitution, a section also known as the Bill of Rights.
In the post-Civil War era, many states passed laws that were in conflict with the federal constitution by infringing the rights of citizens. Contrary to the constitution’s language, for example, people were regularly deprived of their liberty without “due process of law,” meaning in many cases a trial by jury.
At this time, the protection of rights outlined in the original U.S. Constitution applied only to the federal government alone. State governments had their own constitutions, which did not always match the language of the federal document. Laws passed by the state only had to conform to the language of the state constitution, not the federal constitution.
Supreme Court Decisions
After the passage of the 14th Amendment, the Supreme Court made a series of decisions that selectively applied the Bill of Rights to the individual states. Eventually the first eight Bill of Rights amendments were incorporated in this way, including the right to a trial by jury. Each state, as well as the federal government, must protect these rights of their citizens -- and no state may pass a law infringing these rights.