The Tenth Amendment.
Step-by-step explanation:
The Tenth Amendment in the United States Constitution states that all of the powers that are not delegated to the national government are given to the states.
The main concern with the United States Constitution was the amount of power the national government was going to have. Many people were nervous of tyranny, as they had just broken away from British rule.
In order to prevent this and still give the states their own powers, they made it so any powers that are not reserved for the National government can go to the states.