I find it amusing at how many Americans seem resistant to a national ID system, but blithely give out their social security number to any number of private entities, along with their DOB, full name, mother's maiden name, etc. Basically a ready made identity theft kit when the inevitable data breach occurs.

You already have a national attempt at a GUID per human, it's called a social security number, it just has incredibly lax security and data handling practices, and no teeth in penalties for its misuse.