The Electoral College is, as most people know, a very strange institution. Adopted as a compromise after the Constitutional Convention of 1787 was unable to agree upon any of the many other suggestions for how to determine the President, it is unique worldwide among the countries that elect an executive president. Other countries use direct election with a single district (the entire country): many use plurality voting, many others plurality with runoff, and Ireland and India use instant runoff (called Ranked Choice Voting these days in the US). The US has a system whereby each state sends representatives (electors) to decide who will be president (if they can – there are special procedures if they cannot agree, requiring Congress to get involved).
Direct election was less palatable to small-population states. Because representation in the House is somewhat biased toward very small states (like Wyoming, who must be allocated at least one seat) and the Senate is clearly biased in that way (since each state gets 2 senators regardless of population), the current system is presumably still preferred by small states to direct national election.
One other reason for the compromise was that states still practicing slavery at the time were allowed to count slaves as 3/5 of a non-slave for the purposes of determining the voting weight of the state, whereas under direct election they would (presumably) not have allowed slaves to vote and therefore had less influence. I don’t know whether anyone seriously considered allowing slaves to vote, but I doubt it. In any case, this reason for supporting the Electoral College is no longer valid. However, voting weight is proportional to population, not the population of eligible voters, so that states with unusually high fractions of non-citizens or children will still benefit relative to other states from the current system. I have not been able to find statistics on the breakdown by state of residents ineligible to vote. It seems that foreign-born residents of the US make up less than 15% of the population. Of these, about half are noncitizens, and about half of these are illegal immigrants.
The Electoral College is another example of first-mover disadvantage incurred by the US, and the difficulty of changing the Constitution has made it hard to remove. According to Wikipedia, there have been over 700 attempts to remove or change the EC system. As so often, however, the Constitution gives considerable leeway in terms of implementation. The original idea of many of the framers of the Constitution was that the electors chosen by each state would convene, like cardinals selecting a pope, and make their choice.
Each state’s electors are chosen by the state legislature. Although public election of electors was not specified, within a few decades most states were using public elections, and for more than 150 years this has been the only way electors are selected. Some of the founders expected that electors would be chosen from voting at a district level, but in all states but Maine and Nebraska, they are now chosen by statewide voting with the plurality winner of the presidential election in that state being allocated all of the electors. About two-thirds of states have laws requiring that electors vote as instructed, and only about half of those have any enforcement mechanism – in most of those, but not all, an attempted “faithless” vote will be canceled and the elector replaced. So in theory it is possible for enough electors to vote otherwise than instructed to change the result of the election. This has never happened, but it seems a system very open to bribery and coercion of electors.
It seems clear enough that in the modern world with electronic communication, and where the idea of appointing electors to use their own judgment is out of step with what we think of as democracy, that each state’s electoral college votes be simply reported. It is also strange that so many states give all their votes to the plurality winning candidate, rather than allocating them proportionally, as for example is done in the Democratic Party primaries.
Of course, scrapping the entire EC system and replacing it by a nationwide vote would probably be best. The compromise allowing increased Congressional power for small states, and the idea of separation of powers, seem to make it clear that the President should not be determined by Congress or in a way that allows individual states disproportionate influence. The Constitution bars federal office-holders from being electors.
In 1969 Congress came as close as it ever has to changing the Electoral College when the House passed a law proposing a constitutional amendment to abolish the EC and institute a nationwide vote for President using a plurality runoff system similar to the French one. The bill did not pass the Senate (being opposed by representatives of small states). If it hard, it would still have had to be ratified by 2/3 of the states.
Given the difficulty of amending the Constitution and the self-interest of states, scrapping the EC seems unlikely to happen soon. Some states have tried to circumvent the system by agreeing to allocate all their votes to the winner of the nationwide popular vote, but this currently seems to have stalled and might face legal challenges if enacted. So the next best option may be for states to award their votes proportionally. This runs into self-interest of states: some who are currently reliably controlled by one party will want to keep things that way (set against is that more states would become swing states and require candidates to campaign more seriously there). At least it is possible to see this practice taking hold slowly, state by state.