Watch the most interesting bit ... (Score 4, Informative)

If you don't have the time to watch the entire thing ... start watching at 1:05:15 until at least 1:16:00 ... which includes Diebold stating that the memory cards cannot be hacked without the system knowing, and then watching the process of the memory cards being hacked and altering the outcome of an election (and the system not registering the fraud). All it takes is to preset the cards with a number of negative votes for one candidate and the same number of positive votes for another candidate (thus not altering the total number of votes cast).