On National Identity Cards

Why can't we have an identity card? My family has recently been the victim of identity theft. If we had some sort of biometric card with a number that could only be decoded with a fingerprint or iris check, then it would be a whole lot harder for someone to jack your social security number and pretend to be you. Have a card and don't give people credit unless they ARE who they say they are. It is technologically feasible isn't it?

For you black helicopter people: They already know who we are. They already have us pegged in their databases. Unless you live off of the grid in the middle of nowhere, they (the government) have your number. (And I'd be all for making the National ID card voluntary) Why not at least keep it out of the hands of the criminals?