What amendment states that the Electoral College will vote separately for President and Vice President?

The amendment that mandates the Electoral College to cast separate votes for President and Vice President is the 12th Amendment. Ratified in 1804, this amendment was introduced to address issues that arose in the early electoral processes, particularly the election of 1800, which resulted in a tie between Thomas Jefferson and Aaron Burr.

The 12th Amendment established that electors would cast distinct ballots for President and Vice President, clarifying the process and reducing the possibility of confusion and conflict. This was a significant change from earlier practice, where the candidate receiving the highest number of votes would become President and the runner-up would become Vice President, often leading to a President and Vice President from opposing political factions. By creating a separate voting process, the amendment ensured a clear distinction between the two offices and promoted political coherence within the executive branch.