it is presumed, that the juries are the best judges of facts; it is, on the other hand, presumed that the courts are the best judges of law. But still, both objects are within your power of decision. You have a right to take upon yourselves to judge of both, and to determine the law as well as the fact in controversy.~ SCOTUS
AS the federal government was created by and empowered by the states, the states should always be assumed to have the primary right to determine whether or not the federal government is acting within the limits set by the states in the Constitution. It is this lack of oversight that has allowed the federal government to assume far more power than was ever delegated. However, because the people also elect delegates to the federal government they also have a right to determine whether or not the federal government is conforming to the limitations of the Constitution.
Within each state the sole power of determining compliance with state constitutions lays with the people. Since the US Constitution is in fact a contract or compact between the states it is primarily the responsibility of the other states to judge whether or not the actions of a particular state fails in its obligations to the US Constitution.~ Robert Karnes