Diebold voting machine controversy (2003-2006)
US election officials adopted touch-screen voting machines from Diebold and other firms, most without paper trails. Journalist Bev Harris documented flaws in her 2004 book Black Box Voting, and Princeton researchers demonstrated in 2006 that a computer virus could alter votes on a Diebold machine within minutes.
States and vendors added paper trails; some jurisdictions reverted to paper ballots.
Led to widespread voter-verified paper audit trail (VVPAT) requirements and independent testing standards for election software.
Shows how doubts about election software, even without proven fraud, can force audits and redesigns of voting systems.
