Each State shall appoint, in such Manner as the Legislature thereof may direct, a Number of Electors, equal to the whole Number of Senators and Representatives to which the State may be entitled in the Congress: but no Senator or Representative, or Person holding an Office of Trust or Profit under the United States, shall be appointed an Elector. --Constitution, Article 2.1

Electoral College

Explanation:

The election of the President of the United States is made by Electrol college. The Founders did not want a few populated states would determine the election of the president in their new nation. This would risk leaving less populated states without a useful context to be identified in the procedure. The electors shall assemble in their respective States and vote by ballot for two individuals, and they shall create a list of all the individuals voted for and the number of votes cast for each. The one who gets the highest number of votes shall be elected as the President.

because it took place after the war of 1812 had come to an end.