12th Amendment

The Twelfth Amendment to the United States Constitution establishes the procedure for electing the president and vice president, replacing the original system in Article II, Section 1, Clause 3. Under the new rules, each member of the Electoral College casts one electoral vote for president and one for vice president. This change eliminated the possibility of electing a president and vice president who are political opponents, which occurred in the 1796 and 1800 presidential elections. The amendment was proposed by Congress on December 9, 1803, and ratified by the required three-fourths of state legislatures on June 15, 1804, taking effect for the 1804 presidential election.learn more on wikipedia