10th Amendment

Something to keep in mind as candidates unveil their proposals during the presidential campaign:

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.

Those powers delegated to the United States can be found here, here and here. On a related note I believe that there is a proposal being floated by some Republicans in Congress that would require every piece of legislation to list the part of the Constitution that allows it.