Under our Constitution, the President is elected by “electors.” There are currently 538 electors. To win, a candidate needs a majority of all electors appointed, so 270.
State legislatures decide how electors are chosen. Initially, many legislatures chose the electors directly themselves. Since 1876, every legislature had given the voters in their state the presumptive choice of electors through an election.
When people vote for the President on this year’s November 3 election day, the results of the popular vote in each state determines which party sends its slate of electors to represent that state in the Electoral College. How electors are chosen differs from one state to another. On December 14, those “electors” then gather in their state to cast their vote for President.
The electors’ votes are then transmitted to Congress. On January 6th, the new Congress, which is seated on January 3rd, is to gather in a Joint Session to count those votes. The candidate who receives a majority (270) is elected President.