After Americans won the Revolutionary War, America's Founding Fathers realized that they would need some rules to help govern their new country.

They decided to create a document called the Constitution. One way to think of the Constitution is as the law that governs the government. The Constitution is the set of rules and regulations that define the powers and duties of the government. When the Founding Fathers wrote the U.S. Constitution, they did something very important—they gave some power to the national government or federal government and some to the states. By doing this, they made sure that no one group would have too much power.