another faithless elector in the 1800 election had voted twice for Aaron Burr, but under that electoral system only votes for the president's position were cast, with the runner-up in the Electoral College becoming vice president (and the second vote for Burr was discounted and re-assigned to Thomas Jefferson in any event, as it violated Electoral College rules).
In the 1800 election, why did Thomas Jefferson get the second vote?
it violated Electoral College rules