Complex sentence: To rectify the flaw in the original presidential election mechanism, the Twelfth Amendment, ratified in 1804, was added to the United States Constitution, stipulating that electors make a discrete choice between their selections for president and vice-president.
Split into simpler sentences: To rectify the flaw in the original presidential election mechanism, the Twelfth Amendment, ratified in 1804, was added to the United States Constitution. It called for electors to make a discrete choice between their selections for president and vice-president.