Trump won a clear majority of those electors -- 306, despite losing the popular vote to Democrat Hillary Clinton
When US voters cast their ballots on November 8, they did not directly elect the next president but rather 538 "electors" charged with translating their wishes into reality.
Trump won a clear majority of those electors -- 306, with 270 needed for election -- despite losing the popular vote to Democrat Hillary Clinton by nearly three million votes.
On Monday the electors - most of whom are party members with little name recognition - will convene in each state plus the District of Columbia to officially designate the next president and vice president.
Following an extraordinarily vitriolic campaign, this step in the electoral process, which is normally a mere formality, has been thrust into the spotlight.
To prevent Trump from becoming president, Democratic activists must convince at least 37 Republican electors to abandon their candidate.
One Texas Republican elector, Christopher Suprun, has publicly said that he will not vote for Trump.
Trump "shows daily he is not qualified for the office," Suprun wrote in The New York Times in early December.
"The election of the next president is not yet a done deal. Electors of conscience can still do the right thing for the good of the country," Suprun wrote.
An online petition calling on electors to reject Trump has collected some five million supporters. Hollywood stars including Martin Sheen ("President Bartlet" on the TV series "West Wing") recently released a video to goad electors to dump Trump.
If Trump were to lose the electoral college vote it would be up to the House of Representatives - controlled by Republicans - to designate the successor to President Barack Obama.
But there is no evidence that enough Republican electors will abandon Trump.
The final vote result may not be known on Monday, as states are given several days to report their numbers. Congress will announce the name of the winner on January 6, two weeks before the next president is to be inaugurated.
Russia's alleged cyber hack that many Democrats believe gravely wounded Clinton has added an extra layer of drama to the electoral college vote.
Ten electors - nine Democrats and one Republican - wrote an open letter to National Intelligence Director James Clapper seeking an intelligence briefing on the matter ahead of their vote.
Clinton's former campaign manager John Podesta, whose e-mail account was hacked during the campaign and thousands of his private messages were spilled into the public, supported the request.
Clapper, however, said no.
The incoming White House chief of staff, Reince Preibus, told Fox News on Sunday that the pressure on the electoral college not to elect Trump is "about Democrats that can't accept the outcome of the election. It's about delegitimizing the American system."
Now they're going forward "with this attempt to intimidate and harass electors. We have electors receiving 200,000 e-mails. Nothing is going to change," Preibus said.
Trump himself weighed in via Twitter.
"If my many supporters acted and threatened people like those who lost the election are doing, they would be scorned & called terrible names!" he wrote.
Not all Democrats support trying to get Republican electors to reject Trump.
"Though I share deep concerns about election & @realDonaldTrump," former senior Obama aide David Axelrod wrote on Twitter, "most electors will follow states & should. Reversal would rip country apart."