In Ray v. Blair, the U.S. Supreme Court holds that a state cannot constitutionally require its electors to vote for the candidates to whom they are pledged. There have been at least four instances in which individual electors failed to vote for the candidate to whom they were pledged. One occurred in 1820, when an elector pledged to James Monroe voted for John Quincy Adams. His rationale was that his vote would have made the election of Monroe unanimous and that no president other than George Washington was deserving of unanimous support. The three other instances – 1956, 1960 and 1968 – were equally peculiar to the individual elector. None affected an election’s outcome.