It functioned only as a court system, but now it is able to perform "Judicial review" (basically determining if a law is Constitutional or not)
Explanation:
The Articles of Confederation originally left out the Judicial Branch. In the Constitution all that is stated is that "[t]he judicial Power of the United States, shall be vested in one supreme Court, and in such inferior Courts as the Congress may from time to time ordain and establish.” It did not elaborate or establish an initial purpose for the branch, but instead left it all up to Congress. Later with the Judiciary Act the Supreme Court was established, which gave the Judiciary Branch the role of functioning as a court system. During the tenure of John Marshall, the Supreme Court expanded its purpose by declaring a state law unconstitutional in the "Fletcher v. Peck" case. This established the role of the Judicial Branch in Judicial review.
World War II convinced U.S. leaders that the policies of isolationism and appeasement had been mistakes. To counter the growing Soviet threat, they sought new ways to keep the U.S. safe and protect its interests abroad.
