Why was a direct election rejected as a method for electing a president?

Many today want to get rid of the electoral college method of choosing our ... Deciding how to select orelect the president was one of the most difficult ... The Founding Fathers considered direct election

There's actually a big debate among historians about why the framers decided to elect the president indirectly (via the Electoral College) rather than directly through a popular vote.

The most common argument is are that a popular vote gave too much of an advantage to the more heavily populated northern states—something the more rural southern states were obviously opposed to.

Another argument is that the Electoral College was designed as a way of protecting the institution of slavery. A popular vote would threaten the political future of legal slavery because if northern states voted to give voting rights to freed slaves and African-Americans, then the north would consistently be able to outvote the Southern states, who wanted to protect slavery at all costs.

Here's an explanation of how the Electoral College gives a slight advantage to lower-population states. Each state gets at least three electors—one for each senator and one for each representative in the House. So even if a state hypothetically had only 99 citizens, it would technically still get three votes in the electoral college, which amounts to one electoral vote for each 33 citizens. Meanwhile, a state with 999,000 citizens might also get only 3 electoral college votes, depending on how the House is apportioned with each census. This would mean one electoral vote for every 333,000 citizens. Obviously the advantage in this case goes to the citizens of the smaller state, who have much more say in who their electors vote for.