What is the incorporation doctrine? How did it work to grow the power of the federal government?

The incorporation doctrine is a constitutional doctrine through which the first ten amendments of the United States Constitution, known as the Bill of Rights are made applicable to the states through the Due Process clause of the Fourteenth Amendment. Incorporation applies both substantively and procedurally.

Over a succession of rulings, the Supreme Court has established the doctrine of selective incorporation to limit state regulation of civil rights and liberties, holding that many protections of the Bill of Rights apply to every level of government, not just the federal.