It's not only your SSN that is a national ID number, thanks to the Real ID Act your driver's license/state ID number is your true national ID number. At least,

It's not only your SSN that is a national ID number, thanks to the Real ID Act your driver's license/state ID number is your true national ID number. At least, that was the plan, but literally half the states and territories are holding out and stalling it, so the SSN continues to be that default ID number for anything federal. I don't know which is worse: The cock-up that is the Real ID Act or the stupidity surrounding the SSN being a de facto ID number for anything and everything.