What is the supremacy clause and why is it important?
The Supremacy Clause states that the US Constitution is the supreme law of the land. This is what makes it important and it is outlined in Article 6, Clause 2 of the Constitution.
What is the clause in the US Constitution gives the central government overall authority over the states?
What prevents the federal government from using the supremacy clause to take all powers away from the states?
Congress is only able to take action using the Supremacy Clause if its actions are within an area in which Congress holds authority. If it doesn't have the authority, the Supremacy Clause is invalid. Intent also needs to be established. In other words, the law must have been created for the purpose of superseding the policy of the state.