9 dez 1803 ano - The proposed Twelfth Amendment to the United States Constitution, requiring that electoral ballots distinctly list the choice for president and the choice for vice president, is approved by Congress for submission to the states for ratification; passed in the wake of the problems in the 1800 presidential election, the amendment is ratified by 13 of the 17 states and is proclaimed in effect on September 25, 1804 (Linha do tempo)