I.

Introduction

Bill of Rights, first ten amendments to the Constitution of the United States. The Bill of Rights establishes basic American civil liberties that the government cannot violate. The states ratified the Bill of Rights in 1791, three years after the Constitution was ratified. Originally the Bill of Rights applied only to the federal government, but in a series of 20th-century cases, the Supreme Court decided that most of its provisions apply to the states. Many countries have used the Bill of Rights as a model for defining civil liberties in their constitutions.