To answer the OP, the United States was set up as a federal republic, wherein sovereign States agreed to a central government with limited powers. As such, the States themselves selected the President according to a process which mirrored the composition of the House and Senate. The method of selecting Presidential Electors was and still is left to the States:
"Except for the electors in
Maine and
Nebraska, electors are elected on a "winner-take-all" basis.
[2] That is, all electors pledged to the presidential candidate who wins the most votes in a state become electors for that state. Maine and Nebraska use the "congressional district method", selecting one elector within each congressional district by popular vote and selecting the remaining two electors by a statewide popular vote." -Wiki
Thus, the direct popular election of the President is opposed in large States, whose power and influence would be diluted by proportional assignment of electors to each candidate, and in small States, who fear that vote manipulation in large urban areas could sway a national election. The first step towards reforming this system would be to require proportional selection of all electors, but this would never be supported by the Democratic states.
The method of selecting Presidential Electors was and still is left to the States.
For states seeking to exercise their responsibility under the U.S. Constitution to choose a method of allocating electoral votes that best serves their state’s interest and that of the national interest, a proportional method falls far short of the National Popular Vote plan.
Support for a national popular vote is strong among Republicans, Democrats, and Independent voters, as well as every demographic group in every state surveyed recently. In the 41 red, blue, and purple states surveyed, overall support has been in the 67-81% range -in rural states, in small states, in Southern and border states, in big states, and in other states polled.
Americans believe that the candidate who receives the most votes should win.
The National Popular Vote bill that would guarantee the presidency to the candidate with the most popular votes in the country.
It would make every person's vote equal and matter to their candidate because it guarantees that the candidate who gets the most votes in all 50 states and DC becomes President.
All of the presidential electors from the enacting states will be supporters of the presidential candidate receiving the most popular votes in all 50 states (and DC)—thereby guaranteeing that candidate with an Electoral College majority.
The National Popular Vote bill has passed 33 state legislative chambers in 22 rural, small, medium, large, Democratic, Republican and purple states with 250 electoral votes, including one house in Arkansas (6), Connecticut (7), Delaware (3), The District of Columbia, Maine (4), Michigan (16), Nevada (6), New Mexico (5), North Carolina (15), Oklahoma (7), and Oregon (7), and both houses in California, Colorado (9), Hawaii, Illinois, New Jersey, Maryland, Massachusetts, New York, Rhode Island, Vermont, and Washington. It has been enacted by small, medium, and large states -- the District of Columbia (3), Hawaii (4), Illinois (19), New Jersey (14), Maryland (11), California (55), Massachusetts (10), New York (29), Vermont (3), Rhode Island (4), and Washington (13).
38 small, medium, and large states in 2012 had no political power or influence in the general election campaign.
Analysts already conclude that only the 2016 party winner of Florida, Ohio, Virginia, Nevada, Colorado, Iowa and New Hampshire (with 86 electoral votes among them) is not a foregone conclusion. So, if the National Popular Vote bill is not in effect, less than a handful of states will continue to dominate and determine the presidential general election.
More than 99% of presidential campaign attention (ad spending and visits) was invested on voters in just the only ten competitive states in 2012.
Two-thirds (176 of 253) of the general-election campaign events, and a similar fraction of campaign expenditures, were in just four states (Ohio, Florida, Virginia, and Iowa).