Combine elctoral machines with security vulnerabilities and what do you get? A PR disaster for Diebold. Diebold's actions in dealing with this issue and the vulnerabilities in their products - can you say mission critical for democracy? - are a case study in how not to deal with a vulnerability. Almost all software is vulnerable to attack and so few companies are capable of dealing these problems gracefully.
Here is a good summary of the movement against Diebold.