There is no national popular vote.
Apparently you have not heard of the National Popular Vote Interstate Compact to which, as of March 2020, has been adopted by 15 states and the D.C. Colorado has suspended it. These 15 states comprise of 196 electoral votes. Currently, a candidate would need 270 Electoral College votes to win the Presidency.
This Compact was devised so that the Candidate with the most votes nationally would get the electoral college votes agreed to in the compact. The states are saying that they can get around this per the US Constitution where Article II, Section 1, Clause 2 states (paraphrasing) that each individual state legislature can define the method in which to appoint its electors in the Electoral college.
This is a bonafide way to steal an election since each can now mandate that all electors must vote the way the state determines, voters be damned in that state. This has not been challenged in the Supreme Court at this time but the current decision on “faithless” electors means a great deal when 73% of the total number (at least 270) of electoral votes to win are put in the hands of only 37% of states.(15 out of 50 plus the D.C.).
I firmly believe this decision leans towards the states on the National Popular Vote Interstate Compact when it is challenged in the SCOTUS, Had the decision fallen the other way, it would have meant the end to the Compact.
So technically there is not a National Popular Vote per the Constitution but with the overall votes tallied a Presidential Candidate can lose the Overall Popular vote due to population density in certain states and win the Presidency via the Electoral College. This happened 5 times (1824, 1876, 1888, 2000 and 2016) since the beginning of this country.
Still, has such interstate compact been ratified by Congress? I think it is Article2 section 4, maybe 8 wherein State are prohibited from entering into compacts etc w/o congressional approval.
Four of the five times that the “winner” of the popular vote failed to win the electoral vote, that person had less than 50% of the popular vote. The exception was 1876, where Tilden may have had a slight majority of the popular vote (like 51%), but there was so much fraud in that election that I don’t know if we can state that for sure.