Some Princeton researchers made a demonstration video of how it’s possible to steal an election with a Diebold voting machine in under a minute. Anyone with physical access to the machine can put in malicious software to steal votes’such as election workers who have unsupervised access to the machines before elections. All they have to do is open up the machine with a key (or pick the lock), remove the old memory card, stick in your own memory card, boot the machine, and it automatically installs any software that was on the memory card.

Thanks to Sphinx for pointing me to this website. You can go here to watch video and read more.