1800 United States presidential election

Thomas Jefferson and Aaron Burr tied at 73 electoral votes each, and the Federalist-controlled House needed 36 ballots, ending on February 17, 1801, to choose Jefferson. The deadlock led to the Twelfth Amendment, which has electors vote separately for president and vice president. The deeper shift was partisan. National power passed from John Adams's Federalists to Jefferson's Democratic-Republicans, and the Federalists never again claimed the presidency, largely disappearing during James Monroe's time in office. For anyone tracing realignment, this is the starting point: the first real test of whether one organized party would hand the government to another.