The Electoral College was established by the founding fathers as a compromise between election of the president by Congress and election by popular vote. Each State's allotment of electors is equal to the number of House members to which it is entitled plus two Senators. The decennial census is used to reapportion the number of electors allocated among the States. The slates of electors are generally chosen by the political parties.
State laws vary on the appointment of electors.
The States prepare a list of the slate of electors for the candidate who receives the most popular votes on a Certificate of Ascertainment. The Governor of each State prepares seven original Certificates of Ascertainment. The OFR forwards one copy to each House of Congress and retains the original. A majority of 270 electoral votes is required to elect the President and Vice President. No Constitutional provision or Federal law requires electors to vote in accordance with the popular vote in their State.