I'm somewhat familiar with the Sequoia AVC case in New Jersey, from a Usenix paper by Appel et al.:

We found two design flaws of the AVC Advantage which may cause inaccuracy in counting votes [...] Thus, a voter may mistakenly think she has voted, when she has not; or a voter may vote, and then be invited to vote again by a pollworker who mistakenly thinks her vote was not recorded.
They are also consistent with a 1% undervote observed in the one precinct in which we subpoenaed “voting authority” stubs. In precinct 6 in Pennsauken, NJ on February 5, 2009, there were 283 Democratic voting-authority stubs but the public counters of the 3 AVC Advantage machines added up to only 280, with 280 votes recorded.

The Sequoia machine was used more widely than that, but it seems the paper refrained from estimating the total number of people disenfranchised.

What are some large cases (in absolute numbers of voters disenfranchised) in the US due to problems with electronic voting machines? Of course, numbers can never be entirely certain in such cases, so estimates are likely to be reported. To prevent this question from becoming a conspiracy theory magnet, such estimates would have to be published by reasonably authoritative sources.

Best/accepted answer goes to the largest number reported in an incident, as long I judge the analysis to be reasonably authoritative and evidence supported.

  • 8
    The main issue really is the lack of trust, due to lack of verifiability with no physical voting artifact. There could (theoretically, I'd like to think not realistically) be huge incidents we don't know about due to there not being any hardcopy votes to double-check against. Just as importantly, if some sore loser claims the computers cheated him, there's no way to prove that loser wrong.
    – T.E.D.
    Aug 6, 2018 at 18:45

1 Answer 1


This example is probably the most notorious because the undervote was so large, in absolute terms but especially as measured by percentage of the vote and the margin percentage of victory:

In the 2006 Congressional race in Florida’s 13th District, candidate Vern Buchanan was reportedly ahead of candidate Christine Jennings by 369 votes. However, in Sarasota County, one of the five counties in the District, a staggering 18,000 votes were not recorded for the Congressional race. That was a higher under-vote rate (almost 13%) than in any of the other counties (in other counties, the highest under-vote rate was just under 6%, and the others were between 2% and 3%). ...in 2006 Sarasota County used paperless DREs. Therefore, there were no independent records of the votes cast in the polling places in that county. Some, including the U.S. Government Accountability Office, ultimately concluded that the under-vote was the result of a confusing touch screen ballot that caused voters to overlook the Congressional race. But because there was no evidence (paper ballots) that could be reviewed to confirm the intention of the voters, there was no way to dispute the electronic result. Following a lengthy legal battle Vern Buchanan was sworn in.

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    Ever since the 2000 Tallahassee Tally Hassle, I've been convinced that fill-in-the-oval optical-scan paper ballots like we use in KC, KS, are the best voting method. Running them through scanners doesn't modify them the way "hanging chads" can be flipped to and fro by the counting machines. And hand-counted audits to confirm 100% accuracy (which should be repeatable) can always be done. Aug 6, 2018 at 19:18
  • 7
    Optical scanning is the only way to securely count votes electronically, and they ought to be counted twice with equipment from different vendors. If both machines give the same result, great. If not at least one of them is provably wrong.
    – hlovdal
    Aug 6, 2018 at 23:28

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