Between your Social Security number and the electronic trail you leave via credit cards, anyone who wants to can "track your every move" already.

Obviously this national-ID-card thing brings the conspiracy theorists out of the woodwork, but if you have a Social Security card, a US passport and a driver's license.. and you're therefore in THREE massive databases... what's the problem with a national ID? It's not like carrying any of the foregoing infringes on personal liberties. I just don't see it.