Why? Obviously it would be a big undertaking, but the post office already issues US Passports. I'm not sure what you mean by "verifying mailing addresses" because the USPS does provide a way to do verify the correctness and deliverability of an address [1].
The point is that the USPS would be in a good position to become the government body that implements a national identity service.
The State Department issues US Passports, the Post Office merely accepts your applications on their behalf.
> I'm not sure what you mean by "verifying mailing addresses" because the USPS does provide a way to do verify the correctness and deliverability of an address [1].
It's only vaguely tied to identity. I have my physical address, but because I live in an RV park and move often, I don't actually receive mail there. In about half of the locations I've stayed, you _can't_ receive mail there.
I use a private mailbox along with a mail forwarding service in order to receive postal mail.
> [1] https://en.wikipedia.org/wiki/Address_Management_System
Is used to solve the problem of sorting and routing mail, which is really what the Post Office spends most of their effort on. Every postal address in the US can be uniquely identified by an 11 digit code: your ZIP+4 and the last two digits of your house number, but it completely ignores multi-tenancy and has no provisions for linking to identity.
Is that more market ideology ("public services are by necessity so dumb") speaking, or is there something specific with the US postal service?
The USPS is nowhere near equipped to handle this. And there's no way I'd trust them to be competent enough to handle the task with the level of security that it would entail.
> They already provide a physical-to-identity "mapping" service for the vast majority of Americans.
They really don't. Even if we ignore the fact that one's identity is completely separate from the question of where they reside, the USPS has no way to verify residence. They don't really even a way to verify mailing addresses, which is at least a more well-defined problem than residence.