How has the Supreme Court ruled regarding the application of the Bill of Rights?

The correct understanding is that the Supreme Court has interpreted the Bill of Rights to apply to the states through the Fourteenth Amendment, specifically via the doctrine of incorporation. Initially, the Bill of Rights was intended to limit only the federal government's powers and actions. However, in the early 20th century, the Supreme Court began to apply certain rights contained within the Bill of Rights to the states through the Due Process Clause of the Fourteenth Amendment.

This incorporation process has allowed many fundamental rights, such as freedom of speech, the right to a fair trial, and protection against unreasonable searches and seizures, to be enforced at both federal and state levels. Over time, through various landmark cases, the Court has systematically determined which rights are considered essential to the concept of due process, ensuring that individuals are afforded these protections regardless of whether they are in a federal or state jurisdiction.

Thus, the application of the Bill of Rights to the states emphasizes the importance of protecting individual liberties against state action, ultimately reinforcing the principle that rights belong to individuals, not just to citizens at the federal level.