On election day in 1800, Thomas Jefferson won a clear victory over John
Adams but almost did not became President. The Constitution required
that presidential electors cast two ballots; the winner became President
and the runner-up became Vice-President. Jefferson’s running mate, Aaron
Burr, who had been nominated for Vice-President, received 73 electoral
votes, the same number as Jefferson. This strange situation occurred
because the Constitutional Convention had not anticipated the rise of
party politics. When John Adams had defeated Jefferson in 1796,
Jefferson, as the runner-up, was elected Vice-President. If parties had
not developed by 1800, Adams, as Jefferson’s opponent, would surely have
become Vice-President. But because parties had arisen, all of
Jefferson’s electors gave Burr their second vote. (A repetition of this
kind of deadlock was avoided for future elections by the Twelfth
Amendment.)
The Constitution stated that if the two leading candidates were tied,
the election should be decided by the House of Representatives. The
trouble was that in 1800 the House was controlled by the Federalists and
not by Jefferson’s party. The Federalists nearly elected Burr President
because they disliked him less than they disliked Jefferson.