The Tenth Amendment
10th: The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.
This one says kind of what the ninth amendment says, except it involves the states. So any rights that aren’t in the first 8 amendments, belong to the people or the state. It means that things that aren’t so big that they are handled by the government (like as marriage or traffic rules,) are for the states, and the people.
