Final answer:
The Due Process Clause of the Fourteenth Amendment has been used to apply many protections of the Bill of Rights to the states, extending key civil liberties beyond the federal level to include state governments.
Step-by-step explanation:
The Due Process Clause of the Fourteenth Amendment is also the means through which many of the protections of the Bill of Rights, which standing alone applies only to federal government, have been applied to the states. This clause, which asserts that no state shall deprive any person of life, liberty or property without due process of law has been used by the Supreme Court to incorporate various portions of the Bill of Rights thereby extending its protections to the state level.
Since its ratification in 1868 the Fourteenth Amendment has played a pivotal role in the expansion of civil rights, including the application of Bill of Rights provisions such as freedom of speech freedom of religion and the rights to due process and equal protection under the law to all U.S. citizens.