It's entirely possible to steal an election. Theft of passwords is not only possible but happens all the time. Once the data is compromised, the results are untrustworthy. Companies that specialize in administering web elections for students readily admit this fact. Nobody can guarantee that it's 100-percent secure.
People use 'digital certificates' now instead of a password.
There's nothing to stop my wife or child from authenticating it. But then you have the big-brother issue. That means there's no 'trusted authority' within the system. There's no one or no group trusted within the system to be able to view, control, add, change, or delete the votes. That's absolutely critical in keeping elections free of fraud.