Although on Nov. 3 we marked ballots listing the names and party affiliations of individual presidential and vice-presidential candidates, we were really voting for slates of electors who are expected to reflect our preferences when they vote on Dec. 14.
On Jan. 6, 2021, Congress will assemble in a joint session to count the electoral votes. If one of the tickets receives 270 or more electoral votes, the presiding officer—the currently sitting vice president—will announce the results. Only with this announcement can the election be “deemed a sufficient declaration of the persons, if any, elected President and Vice President.” This is as required by law in Title 3, Section 15, of the United States Code (3 U.S.C. §15). Inauguration of the newly elected president is scheduled for January 20, 2021.
The Electoral College was created as the result of compromises reached by the delegates to the Constitutional Convention of 1787. The delegates at first wanted Congress to elect the president. As they debated that idea, though, they came to realize that having the president beholden to Congress would compromise the separation of powers that they were trying to create in the new government.
While some delegates then preferred to have the chief executive elected by direct popular vote, the issue of slavery created an obstacle. Suffrage was more widely available in non-slave states than it was in slave states, and there was concern that this would weigh the election in favor of northern states.
They then settled on the idea of indirect election by an Electoral College that was independent of the legislative branch and agreed to number the electors of each state as the sum of congressional representatives (directly elected by population and weighted in favor of slave states due to the Three-Fifths Compromise) and senators (then elected by state legislatures and not favoring any state).
More detailed information regarding the operation of the Electoral College is contained in a recent two-page In Focus report (IF 11641) released by the nonpartisan Congressional Research Service that is available online.