You've heard it before: "the U.S. Constitution is the . Just why is this the case? This clause is found in the United States Constitution, specifically in , clause 2. This establishes the supremacy of the U.S. Constitution: it takes legal to any laws or rulings of the states. This was actually first proposed by William Patterson of the Constitutional convention in his plan of governments. In short, if a law and a law conflict, the national law takes precedence every time. If the US Supreme Court rules an action to be , all states must abide by that ruling.