Everyone is calling candidate Donald trump “President Elect” Trump, some out of courtesy and tradition, but many through sheer ignorance of how the U.S. electoral system works. The popular vote, which Sec. clinton won by 2.5 million votes, counts for nothing; neither does a concession nor carrying most States (and Commonwealths), all that really counts is the December vote in The Electoral College and that hasn’t taken place yet.
At the moment there is no "President-Elect." there is a "presumptive President-Elect."
The Electoral College is all that counts (literally)!
Very few foreigners and actually most U.S. citizens don’t remember that the U.S. isn’t a democracy, it is a republic and they also forget little things like the fact that there aren’t 50 States, there are only 46 States and 4 Commonwealths (Pennsylvania, Kentucky, Massachusetts, and Virginia.) You might consider those mere technicalities, but the law is ALL technicalities.
Voters also forget that voters don’t elect the President or Vice President. They elect mayors, governors and dog catchers.
When Americans thought they were voting for Trump or Clinton, they are really voting for a candidate to The Electoral College, an elector pledged to a party. Pledged, but not always legally obligated to vote for the party's nominee on December 19 when 538 electors place the only votes which actually count. If one half plus one or 270 of them vote for one person, he or she becomes "President-Elect" and their running mate becomes the "Vice President-Elect."
The reason for the electors
The reason The Electoral College chooses the President was because founding fathers worried average people might not be capable of rationally judging whether someone was really qualified to be President, he wasn’t a demagogue and was free from foreign influences, he could take office or, if he failed those two basic tests he could be denied elected office despite winning the public votes.
(Today that's "he" or "she" although the founders never imagined women even voting despite the fact that European empires had both the "weak and feeble" Elizabeth I and Catherine the Great as good examples of women in power when The Constitution was written.)
What if no one gets 270 votes?
If no candidate gets half plus one of the Electoral College votes then the President is selected by The House of Representatives from the top three vote-getters in the Electoral College (each State and Commonwealth, gets one vote so it takes 26 to win) and the VP is chosen by The Senate.
Why this matters
Donald Trump has many foreign business entanglements and every U.S. intelligence agency has determined that Russia interfered with the election on Mr.
Trump’s side.
Alexander Hamilton said in The Federalist Papers (issue 68 - find them in Archive.org) The Electoral College also protects against electing a demagogue. That’s the same “Hamilton” of the Broadway Play Mr. Trump says is overrated with its 11 Tony Awards.
Merriam-Webster defines demagogue as "a leader who makes use of popular prejudices and false claims and promises in order to gain power.“ dictionary.com says a "demagog" is a "political leader, who gains power and popularity by arousing the emotions, passions, and prejudices of the people.”
Mr. Trump ran a campaign "arousing the emotions, passions, and prejudices of the people," Now several GOP Electoral College delegates say they may switch votes and one in Texas says he can’t vote for Trump because of Federalist 68.
If just 12 percent or 37 of the 306 Republican delegates leave Mr. Trump there would be a tie and if 38 vote for Sec. Clinton she would win. Republicans won let that happen, but she could release her 232 electors and Romney got 35 from states where he won in the primary, and any of the 120 electors from states where Romney did well switched, or the draft Kasich movement gains there could be President Elect Romney or Kasich on December 19 which would change everything and ease concerns of many world leaders.