Election Security in a D&D/PF world

[JMS]

The best use of mind control magic would be to use it on the vote counters, not the voters.

Though it's easier to protect a small group... Mandatory Protection from Serpents continual spell pin when you go into the booth to vote, and find a way to deal with the fairly voting Yuan-Ti?
It gets rid of most problems with low level casters, a few Warlocks, or a Mass Suggestion. If a wizard with enough levels to cast Mindrape is meddling, you have bigger problems.