It has been done better in other countries and could be done better in the US if there were political will to do it. There's a whole universe of cryptographically signed certificates that we in the US don't use. The hard part is not signing a cert; it's making sure the certs are given to the correct people and having a procedure for when a cert is lost. Estonia has done this well; Korea has done this poorly. But it's quite doable if you have political will for it.