Answer:
The Supreme Court’s decisions apply to all the States.
If Arizona passed a law that the Court found unconstitutional, that law would be invalid in all the other states. That’s the way they designed the Court.
Before a law gets to the Supreme Court, it goes through the state’s highest court, or the Federal Court for that district. If that court rules that it’s OK, the people against it can appeal to the Supreme Court. If the Supreme Court rules against the law, that law goes away. Sometimes the Supreme Court can decide not to hear a case. when that happens, the law stands.
If the Court decides that a particular law is unconstitutional, Congress can always come up with a revised law.