I’ve been involved in the HAVA implementation here in Minnesota, and a couple of years ago, went to demonstrations given by nearly all the vendors of electronic voting systems.
Minnesota decided to go with the Automark system (already mentioned), but as a supplement to the Optical Sensor machines already used in much of the state. This system does nearly all of what the OP suggested.
But this is a supplement – most people will continue to vote via marking the regular Optical ballot. The Automark system just lets disabled, elderly, or tech-happy people use it to print out a Optical ballot with their marks on it. That ballot is then fed into the same optical scanner/counter as all the other ballots. Ones with errors will be kicked back out, and the voter can try again. (Like DanBlathers examples of voting for more than one candidate.) And the accepted ballots are retained in a locked box if needed for later recounts.
Note a couple of features of this:
- votes from disabled people are treated the same as everyone else. There is no separate tally for them, which could be forgotten, and which could endanger the privacy of their vote. And absentee ballots, too. All voters need at home is a pen to mark their ballot, then they mail it back, and it gets counted with all the other ballots.
- Recounts are done just by running the ballots thru the scanner/counter again. (Or usually, a carefully tuned one at city hall.) So recounts are very, very fast. Typically take a few hours at most.
Many of the proposed electronic systems produce ‘receipts’ that are NOT machine-countable. They could only be counted manually. And the design makes them harder to count than even an old-fashioned paper ballot from 100 years ago. Recounts would be slow and prone to error in such systems. So they would tend not to be done.
Finally, this combination of low-tech (marks on paper ballots) with high-tech (optical scanner/counter machine) works well under pressure. (‘Degrades gracefully’ in systems terminology.)
I’ve seen it at my own precinct when there was a huge volume of voters. People can vote whereever they can use a pen to mark their ballots. All the voting booths were full, but people sat down at the cafeteria tables around the room, or even right on the floor, and filled out their ballots, then brought them up to the scanner. That worked real fast, so only a small line there. With any of the other electronic systems, you can only process as many voters as you have machines. If you have an unexpectedly large turnout, you will have big lines, and some people will leave without voting.
And if the scanner breaks, people can continue to mark their ballots while the workers send for one of the spare scanners from city hall. Voters just turn in their completed ballots to the election judge to be scanned later. They lose the feature of the machine kicking out a ballot that is marked incorrectly (like voting for 2 candidates), but they can still continue to vote.
We’ve even seen this working when the electricity went out at a polling place. The poll workers got out flashlights to read their voter lists, and even put candles at the polling booths so people could see to mark their ballots. (It was in a church meeting hall, so plenty of candles were available.) Rather dark, but voting went on, despite the power failure! That wouldn’t happen with any of the electronic systems.
Finally, there is the matter of costs. This Optical Scanner system is far cheaper than the others. For each voter, all you need is a paper ballot and a pen to mark it, and someplace flat to write on. We use small voting booths that are basically a small table with privacy flaps on 3 sides. They fold up completely into an attache-case size. And they’re pretty cheap. The major expense is one scanner/counter machine needed per polling place (plus a few spares). You can even have more than 1 precinct voting at the same location, because the machines can automatically keep separate counts, even if each precinct has a different list of candidates. All the electronic systems need one machine for each voter, greatly increasing the cost, both in purchasing, maintaining, and transporting these machines.
Having seen pretty much all the other systems, I think the Optical Scan Ballot works best of all in practice.