What Is the role of the supremacy clause in the constitution

This states the the United States Constitution is the Supreme law of the land. Legally, there is not law that any other State or local government can make to supersede the United States Constitution. Any law that goes against the constitution, is technically not a law, and is void. And when these unjust laws come into effect, the people not only have a right to disobey it, they are obligated to.