Article III of the Constitution establishes the judicial branch of Government with the creation of the Supreme Court. Section 1 of Article III begins:

The 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.

Just like its name sounds, the Supreme Court is the highest court in the Nation and is vested with the judicial powers of the Government. There are lower Federal courts, but they were not explicitly created by the Constitution. Rather, Congress deemed them necessary and established them using power granted from the Constitution. Section 2 of Article III gives the Supreme Court judicial power over “all Cases, in Law and Equity, arising under this Constitution”, meaning that the Supreme Court’s main job is to decide if laws are constitutional. It also rules over cases affecting ambassadors, cases of admiralty and maritime jurisdiction, and controversies between two or more states, among others.

When the Supreme Court rules over a case, it is usually deciding arguments about the meaning of laws, how they are applied, and whether they violate the Constitution. The ability to decide if a law violates the Constitution is called judicial review. It is this process that the judiciary uses to provide checks and balances on the legislative and executive branches. Judicial review is not an explicit power given to the courts, but it is an implied power. The Supreme Court made a ruling in 1803 on a case called Marbury v. Madison that clearly stated the Court's power of judicial review.

Now that we’ve learned about Article I, Article II, and Article III of the Constitution, we know exactly why each branch of the Government has the power that it does. You can learn more by reading the Constitution, looking at a diagram of the Government of the United States, or going on more Learning Adventures.