I believe the piece we're missing is the government (citizen?) service which issues (manages, replaces, revokes) constituents' cryptographic tokens for use with such things.
Then our voting systems could be electronic, secure, open, verifiable, and mostly private; assuming effective oversight / this organization does not issue fraudulent tokens or leak keys or identities (big assumption, but I don't think it's impossible.)
Then our voting systems could be electronic, secure, open, verifiable, and mostly private; assuming effective oversight / this organization does not issue fraudulent tokens or leak keys or identities (big assumption, but I don't think it's impossible.)