The Fourteenth Amendment was one of the three post-Civil War amendments the purposes of which were to establish the right to citizenship for all persons born in the United States (Fourteenth Amendment), to extend and expand the guarantees of the Constitution to the States (Fourteenth Amendment), to abolish slavery (Thirteenth Amendment) and to protect the right of all citizens—especially emancipated slaves—to vote (Fifteenth Amendment).
The Fourteenth Amendment imposed the requirements of due process upon all states and compelled the States to extend the equal protection of law to all persons (not just citizens). On the basis of the Fourteenth Amendment Due Process Clause, the Supreme Court held, over a period of years, that most of the rights established under the Bill of Rights and the Constitution—including the First Amendment—apply to the States.