What happens if a law is declared unconstitutional?

IF a law is declared unconstitutional by the Supreme Court, what happens to the law?What happens if a law is declared unconstitutional?
The Supreme Court's decision refers the case back to the lower court that must review the case and change the ruling. A law can remain on the books still. Eventually, the legislature that created the law can remove it from the books. In the meantime, if the law is enforced after the Supreme Court declared it unconstitutional, the person can appeal the case and get off pretty easily. Generally, such laws are not enforced if they are still on the books.What happens if a law is declared unconstitutional?
The law can still stay on the book, but it is unenforceable. A good example of this was in South Carolina in 2005 when the state legislature finally decided to remove miscegenation (interracial marriage) as illegal from the law books. It passed by a slight margin over 50% which is pathetic, but nevertheless was finally removed from the law books. I'm using this as an example because miscegenation, of course, is legal because of the Supreme Court's Loving v. Virginia decision 20 years ago, but it still was on the books of SC even though it was unenforceable.What happens if a law is declared unconstitutional?
The president will veto the bill.