The failings of these machines are well known: With suitable means and the access afforded to a Registrar of Voters, they can be preprogramed to produce any desired result -- despite what the actual votes were.
The means to do so have been demonstrated, and they are simple. The final checkout before voting supposedly examines the totals of each candidate, and these each should individually be zero. However, the software in question does not do this. The totals of all the candidates are summed, and if this comes out to zero, the machine is certified and ready for voters to use.
The rub is that the candidates' vote totals can be pre set with a suitably loaded magnetic card. If one candidate, say, the republican, is set up with a 10,000 vote total to start with and some other candidate, the Democrat, has a minus 10,000 total, the initial checkout will not fail since these two large numbers sum out to zero. Presto! The Democrat starts out with a 20,000 vote hill to climb. The slickest part of this is that the final totals will not indicate that any more votes have been cast than the number of voters. Cute, eh?
That can't happen, you may assert. Then how did a Florida precinct have a final total in minus numbers for Democratic votes in 2004? This would be explained by some underintelligent functionary overestimating the Democratic turnout. Further, how can one explain the sometimes vast difference between exit polls and the final tallies -- almost always favoring the republican? There might have been a few of these in the last election.
These manipulations are only possible because the software -- forgive my lapse into computerese here -- allows signed integers for vote totals rather than only unsigned integers. In regular English this is: How the hell can anyone justify minus numbers even being possible when tallying vote totals? Can anyone actually cast a negative vote?
I believe this quirk is a feature and not a bug. There might be an unexpressed reason why the Bush administration and a republican congress actually voted the money to inflict these voting machines on as many states as possible. For those of you who think they see a budding "conspiracy theory" here, consider this. If I were to seek to mount a successful conspiracy, the first thing to do would be to start a program ridiculing conspiracy theories in general. It would be perfect cover. And who does this?
I suggest that in states where these particular voting machines are still in use and were the administration is republican, Democrats will never win an important election. The candidates won't matter, nor the issues, nor GOTV efforts. The fix would be in before the first vote would be cast. You could have fourteen repugs against a hundred thousand Democrats, and the repugs would win "a stunning upset victory, not indicated by any of the polls!"
Lump it.