"The election of the president and the vice president of the United States is an indirect election in which citizens of the United States who are registered to vote in one of the fifty U.S. states or in Washington, D.C., cast ballots not directly for those offices, but instead for members of the Electoral College.[note 1] These electors then cast direct votes, known as electoral votes, for president, and for vice president. The candidate who receives an absolute majority of electoral votes (at least 270 out of 538, since the Twenty-Third Amendment granted voting rights to citizens of D.C.) is then elected to that office. If no candidate receives an absolute majority of the votes for president, the House of Representatives chooses the most qualifying candidate for the presidency; if no one receives an absolute majority of the votes for vice president, then the Senate elects the vice president." wiki on election of POTUS
To understand federal elections in the US you have to understand that the US government is a truly federal system created by the states after negotiation among them and approval by the states in ratifying conventions. That approval was a near run thing. To protect their interests the smaller, and more thinly populated states demanded and got protections built into the constitution before they would agree to the creation of the Union. Those provisions apply to all later state admissions to the Union.
One of these was that the states would conduct their own AND FEDERAL ELECTIONS. To remove that provision from the US Constitution would require the agreement of the states in the ratification of amendments or of amendments subsequent to a constitutional convention. Needless to say, the smaller states, which are in the majority in the Union are not going to agree to their reduction to something like Australian or German states or, worse yet to the status of French departments.
The question should therefore be, by whom and how is the US presidential election decided. The process is both simple and complex. Each state government by some process satisfactory to itself (usually a popular election) decides how to allocate "electors" who will directly elect the president and vice-president of the US. The number of electors from each state equals the number of US Senators plus the number of members of the US House of Representatives. The president and vice-president are separately elected. The VP is not a deputy president. He/she presides over the US Senate and awaits the incapacitation of the president. Any other duties are things delegated by each president. None are necessary.
The winning candidate must receive an absolute majority (270) votes in the Electoral College. If no one does, then the election of the president is decided by the US House of Representatives where, in this case, each state has one vote. In the same circumstance, the US Senate elects the vice-president.
The opportunities for malfeasance at the state level are obvious. The present situation in Pennsylvania where local courts have decided that mail-in votes with illegible postmarks can be counted for three days after 3 November and that signatures on them do not have to match previous signatures on ballots is an obvious example. This position provides the counters with the opportunity to manufacture however many votes are needed after 3 November.
This overall electoral system was devised to prevent a direct popular national election for president and it does that. The framers, correctly IMO, feared the mob.
There is no real possibility of moving away from this indirect system. The states will not allow it. pl