Final answer:
The theory of incorporation accepted by the U.S. Supreme Court is selective incorporation, which applies the Bill of Rights to the states via the Fourteenth Amendment's Due Process Clause and has been underscored by landmark cases like McDonald v. Chicago and Near v. Minnesota.
Step-by-step explanation:
The theory of incorporation finally accepted by the U.S. Supreme Court is selective incorporation. This theory posits that the Bill of Rights applies to the states through the Due Process Clause of the Fourteenth Amendment. Selective incorporation ensures that various provisions of the Bill of Rights, which articulate fundamental liberties, are upheld by the states even if state laws or constitutions do not provide similar protections.
Starting with the case of Chicago, Burlington & Quincy Railroad v. Chicago in 1897, the Supreme Court embarked on the process of selective incorporation, determining which rights enumerated in the Bill of Rights are essential to the concepts of liberty and justice and therefore must be observed by the states. Cases such as McDonald v. Chicago and Near v. Minnesota highlight this ongoing process where the Supreme Court has incorporated specific amendments, such as the Second Amendment's right to bear arms and freedoms concerning censorship, respectively, into state practice under the Fourteenth Amendment. The incorporation process is crucial in ensuring that the states honor the essential rights and freedoms guaranteed under the Bill of Rights.