The incorporation of the Bill of Rights (or incorporation for short) is the process by which American courts have applied portions of the U.S. Bill of Rights to the states. Prior to the 1890's, the Bill of Rights was held only to apply to the federal government. Under the incorporation doctrine, most provisions of the Bill of Rights now also apply to the state and local governments, by virtue of the due process clause of the Fourteenth Amendment of the Constitution.
Prior to the ratification of the Fourteenth Amendment and the development of the incorporation doctrine, in 1833 the Supreme Court held in Barron v. Baltimore that the Bill of Rights applied only to the federal, but not any state, government. Even years after the ratification of the Fourteenth Amendment the Supreme Court in United States v. Cruikshank, still held that the First and Second Amendment did not apply to state governments. However, beginning in the 1890's, a series of United States Supreme Court decisions interpreted the Fourteenth Amendment to "incorporate" most portions of the Bill of Rights, making these portions, for the first time, enforceable against the state governments. -Wikipedia, state rights