However, I can't get over two problems with that. The ease of hacking and the failure of our democracy to create secure, open-source digital voting (see: Diebold) and the inability to prevent vote-stealing. Think about if on voting day, your employer demanded to use your phone to cast a vote using your account or you'd be fired.

For the former, we could have verifiable votes: you get a anonymous token, and can look up your vote on a public register by that token. The only problem with that approach is that it makes voter coercion (forcing someone to vote a given way) somewhat easier. However, many states already allow absentee ballots, and some (such as Oregon) do all voting by mail with no "polling booth" option, which has exactly the same property.

So, personally, I'd suggest entirely electronic voting, verifiable votes via anonymous tokens, public lists of votes (so anyone can re-run the voting algorithm to check the result), and strong laws against voter coercion (so that employer you mentioned would get prosecuted).