While we Britons use universally-comprehensible pencil and paper for our elections, Americans have sacrificed the democratic process to corporate interests. They use machines to record and count their votes; and in deference to the power of the Almighty Corporation, any kind of reverse-engineering against the machines they use is an offence.
Some jaw-droppingly bad blunders have been made with voting machines. One often-proposed idea is to issue voters with a receipt. This is an exceedingly bad idea. There is nothing to stop the machine from accepting your vote for candidate A, issuing you with a receipt for candidate A, and then recording a vote for candidate B. You might be able to work out from examining the hardware and the software that that was what it was doing; but of course, they embody confidential trade secrets of the manufacturers.
Even if the USA were to make it law that voting machine manufacturers must publish their blueprints, schematics and software listings to allow independent scrutiny (by the tiny minority of the population who can make sense of such information), how can you be sure that the machine that accepted your vote on polling day was actually built in accordance with those plans and running that software?
Now Imagine this on a notice board in a workplace:
All workers taking time off to vote will be expected to show their receipt proving that they voted for the factory owner’s brother-in-law under penalty of dismissal.
Voter receipts do nothing to prevent the following scenario:
Suppose Candidate A receives 500 votes, B receives 390 and C receives 110. These are the actual votes, remember. The announced result, however, is A 380, B 500, C 120. (Note that those figures are not so far out as to be utterly implausible. If they wanted to get a candidate elected in the face of very strong opposition, they might have to field a few extra candidates of their own just in order to split the vote.) You voted for A. You go with your receipt to the Town Hall to check how your vote was recorded, and are correctly told you voted for A. And that’s as far as you can take the matter.
Even if all 499 of the other people who voted for A go and check, they’ll be told — rightly — that their vote was for A. And because (1) they all go in one at a time to check their vote, and (2) there are also many B- and C-voters in there, not one single one of the A-voters will be the slightest bit the wiser that there are really 500 of them, as opposed to the 380 that was announced!
You could only determine that something was amiss if all those A-voters produced their receipts for Candidate A at the same time. And in reality, the proportion of voters who will actually bother even to check their vote will be minuscule.