Both points sound really weak I‘m afraid. From the perspective of a ruler of a country, both are much larger attack vectors for adversaries than opportunities for myself.

> Countries don’t really want unique IDs per person

Given the number is countries that already have those and those that attempt it every few years... I'd say it's not correct.

For spies, you just issue multiple identities - the origin country shouldn't have any issues with that part. It already happened for witness protection level stuff.

For voting... yeah, that's a citation needed. Politicians mostly worry about foreigners coming to vote.

That's BS, you can have spies with or without unique IDs, and there's better ways to get votes than creating fake people.

Also, a lot of countries do have IDs...

Biometrics have made it very hard for spies to have many different identities.