[MichaelBurge]

One solution is to make blackmailing people's votes illegal. Then the risk of someone recording him with a phone or hidden recorder would discourage your boss from blackmailing you. You could also make it illegal to reveal your vote to anyone else, to make it easier to spot coercion.

In extremely dishonest countries where the local courts, police, and election officials are all corrupt, a large mafia-style presence could coerce a lot of people into voting a certain way. But if any of these are at all trustworthy, it seems difficult to coerce anyone. And even then, the mafia abusing too many people(>5%) would cause them to riot.