Identity is a huge topic itself with lots of projects doing fundamental research and experiments but essentially if it's a traditional physical government then it would work like it does today where you would use your government secured ID to vote. Not much would change. If it's a digital government then it would probably be using an identity based on built up history of actions and financial settlements and connections to other highly verified accounts. Ethereum has a project called POAP (Proof of Attendance Protocol) which is a way of identifying that a real person attended a specific event or performed some important action. These POAP badges can't be faked and are already being used for things like being able to vote on certain dev polls if you've attended a Devcon.

> If it's a digital government then it would probably be using an identity based on built up history of actions and financial settlements and connections to other highly verified accounts.

Not sure if I understand this correctly. You mean, an account will be considered "genuine", if it had a long enough history of activity?

Sort of like a credit score matched with landlords who vouch that you rented from them before. The longer that history the harder it is to fake and also the harder it is to just be the same person with multiple accounts. These systems usually have some component of a social graph where people will interact with and vouch for other people and having more and higher quality connections (more verified, connected to someone you know personally is real) gives you a higher legitimacy rating. It's usually up to the organization to set the minimum bar of how verified someone is to be considered unique.