Years ago it was illegal to use the SS# for ANYTHING but Social security. When I went in the Navy I got a separate service number, in fact that number could be used to tell where you were from and the month you were sworn in. I think it was around 74 that the military changed to SS#, that was the camels nose into the tent and the start of a national ID number. It was instituted by President Johnson, a democrat, in 69, as one of the last things he did before leaving office, the army and air force switched first, the navy and marines followed in 72. Prior to that there was a note on the SS cards that said 'NOT FOR IDENTIFICATION' big letters on the bottom of the card, thats what mine has on it. It was one of the big steps towards a police state which is where we are headed now and have been for quite a few years.