Computerized Voting

Not only may this happen again, we will probably never know about it.

Update: From Wired News:

A new poll shows growing support for requiring electronic voting machines to produce a voter-verified paper trail.

Just under half of all respondents -- 44 percent -- said they thought computerized voting systems are unreliable, up from about one-fourth of respondents in other studies. And almost three-fourths said the systems should produce a paper record that the voter can review. Sixty percent said they would vote for a presidential candidate this year who supports requiring a paper trail.