The significance of the Bill of Rights in U.S. governance lies in its role as a safeguard for individual liberties against government infringement. Ratified in 1791, it comprises the first ten amendments to the U.S. Constitution, explicitly protecting rights such as freedom of speech, religion, and the right to bear arms. The Bill of Rights establishes clear limitations on government power, ensuring that citizens retain fundamental rights and promoting democratic principles. Over time, it has served as a foundation for numerous landmark Supreme Court cases, shaping the evolution of civil rights and liberties in America.