The election of 1800 was contentious; John Adams, a Federalist, ran against Thomas Jefferson, a Democratic-Republican. It was the first transfer of power from one political party to another. During the election, the Federalists viewed Jefferson as an unchristian Deist who supported the anarchic French during the French Revolution. The Democratic-Republicans thought that the Federalists under Adams had assumed too much power and were mad about the passage of the Alien and Sedition Acts, which they thought dangerously curbed individual liberty.
The voting in the Electoral College resulted in a tie between Jefferson and Aaron Burr, both Democratic-Republicans, for President. The House of Representatives decided the election, and Alexander Hamilton's support for Jefferson over Burr helped Jefferson ascend to the Presidency. In 1804, Hamilton and Burr would fight a duel (partly over Burr's anger about the 1800 election in addition to other tensions) in which Hamilton was killed.
As a result of the election, the 12th Amendment was passed in 1804, which changed the voting in the Electoral College so that the electors voted for a President and Vice-President at the same time instead of voting for them separately. When Jefferson assumed power after the election of 1800, it was the first transition of power from one political party to another. Jefferson called for peace between the two parties during his inauguration when he said, "We are all Republicans, we are all Federalists."
The election of 1800 is considered a turning point in history because it marked the first time that power was peacefully transferred from one political party to another. The sitting president, John Adams, was defeated for re-election and the Democratic-Republican, Thomas Jefferson, was elected by the House of Representatives after no candidate received a majority in the electoral college. Although this has been accomplished many times in U.S. history without incident, this first time was remarkable as historically, transfers of power from one ideology to another were often accompanied by violence. The electoral campaign between Adams and Jefferson had been particularly bitter and vociferous; however there was no violence and Jefferson took office peacefully. In a conciliatory note, Jefferson commented in his inaugural address:
We are all Republicans—we are all Federalists. If there be any among us who would wish to dissolve this Union or to change its republican form, let them stand undisturbed as monuments of the safety with which error of opinion may be tolerated where reason is left free to combat it.