What are the Compact and Nationalist Theories of the Union?

The United States is a vast country that is divided into fifty states. Each state has some of its own authority and is more or else somewhat separate from the federal government. Some seem to believe the two political theories apply to the United States situation are the compact and nationalist theories. What are the compact and nationalist theories of the union?

The compact theory states that the Union came after the states. That the states created the union, and the union is only a combination of these states. The nationalist theory states on the other hand that the states have no power, that a union is a whole unit, and that the states were created after the union. In conclusion, these are the compact and nationalist theories of the union.