What to do. What to do. Shall we make it our aim to come up with one? Are you interested, or is it so impossible that we should not even try?
By "operational" I assume you mean a definition that can be fit into the process of scientific testing. Please correct me if I'm wrong.
Can intelligence exist without having some attribute of design?
Take the question on face value, please. Try to think about it as if your little brother were asking you and not the boarish oaf on the other end of this keyboard.