But can a state actually invalidate a federal law?
No.
"They can pass a law that says that there are 46 planets, they can pass a law that says that there are 16 days in the week. It doesn't make it so," says Stephen Vladeck, a professor at the University of Texas at Austin School of Law and an expert on federal courts and constitutional law. "It has no effect legally because the Constitution specifically says you can't do that."