So to all the blockchain-proponents etc: remember that it’s not enough for elections to just be safe. They also need to be safe in a way that is obvious to non-cryptographers.
Many countries run elections on paper ballots and with public ally-observeable counting of votes. They do so in rural communities as well as cities with millions of voters. They rarely see voters waiting in line for more than a few minutes. And the costs are neglible in the grand scheme of things.
That is the gold standard for elections, and it’s actually damn easy to achieve.