In the two states with vote-by-mail I've lived in, you can always hand-submit a paper ballot that takes precedence over your mailed one. The only way someone co

In the two states with vote-by-mail I've lived in, you can always hand-submit a paper ballot that takes precedence over your mailed one. The only way someone could be sure you voted one particular way is to monitor your actions for 100% of the time after you mailed the ballot. This is less ideal than voting in person for everyone, as it still has failure cases like sufficiently abusive relationships. But it's an overall improvement over the previous system. Significantly more of the population votes in practice, making the vote a better measure of the ever-nebulous "will of the people".