A SCOTUS decision IS binding to Congress. They can't pass a law doing something that has been deemed unconstitutional unless they first amend the Constitution to explicitly allow them to do that same thing, which is obviously not going to happen.
My original post was operating under the assumption that all branches would abide by the legitimate actions of the other branches. Grandparent is pointing out that sometimes this doesn't happen. Always a possibility, but not something I expect to see very often.