Suppose John Doe is facing criminal prosecution in Florida. He raises a 4th Amendment issue, and the Florida Supreme Court grants him relief. At this point, the state of Florida can appeal to the US Supreme Court, and the US Supreme Court can, if it chooses, review the judgment of the Florida Supreme Court.
What puzzles me is this: at this point, there is no federal harm to either party. True, the Florida Supreme Court might have used an erroneous federal constitutional theory to tie the hands of the Florida Attorney General, but nothing in the US Constitution says they can't do that.
What is the justification that prevents this from being considered an abstract question?