It strikes me as anachronistic to worry about national ID numbers for privacy reasons. With data processing of the 1950's, someone would have needed a single index number in order to gather all records about me into one place. With today's excess computing power, there's no problem doing a kind of fuzzy fill algorithm -- find all my various numbers, record links between them and therefore equate them (MC 1234 5678 8765 1982) = (AMEX 9876 123655 83002) = (SS 788 84 2345) = Carl M. Ellison 2130 Mass Ave; Cambridge 02140 = (617) 876-6644 etc. To aid those who are computationally challenged, this entity could also create its own index number and let others refer to that -- even call it a national ID number. None of this requires a national ID card.