Democratic presidential candidate Hillary Clinton speaks at a campaign event in Milwaukee, Wisconsin, March 28, 2016. Reuters

Republican billionaire Donald Trump has already assumed the role of president-elect, interviewing potential cabinet members and setting up his staff — but another twist in the seemingly never-ending 2016 election has now opened up a far-off possibility that could lose him the White House.

Green Party candidate Jill Stein raised millions of dollars last week to request ballot recounts in the states of Wisconsin, Michigan and Pennsylvania, which all backed Trump. Democratic nominee Hillary Clinton won’t become the next president of the United States if the recount in the Badger State awards her a surprise victory, but if the same outcome occurrs in Michigan and Pennsylvania, the election could be reversed officially.

Stein has vowed to push for recounts in each state ahead of the Dec. 13 deadline by which electoral college disputes must be settled, though Pennsylvania’s strict requirements could prove difficult to overcome. If voters send in the thousands of affidavits needed to demand a recount there and Clinton takes Trump’s Electoral College votes in each state, she will have 278 electoral votes to Trump’s 260 — just above the 270 threshold needed to win the presidency.

Stein posted a live video on Facebook Sunday urging Pennsylvania voters to participate in the recount process so the state can mandate the process ahead of the approaching deadline. Meanwhile, the Clinton campaign wrote in a Medium post titled "Listening and responding to calls for an audit and recount" that it will participate in the recount in states where the Green Party is spearheading the process — as affected campaigns normally do.

Democratic presidential nominee Hillary Clinton is joined by President Barack Obama at a campaign rally on Independence Mall in Philadelphia, Penn. on Nov. 7, 2016, the final day of campaigning before the election. Reuters

"This election cycle was unique in the degree of foreign interference witnessed throughout the campaign: the U.S. government concluded that Russian state actors were behind the hacks of the Democratic National Committee and the personal email accounts of Hillary for America campaign officials, and just yesterday, the Washington Post reported that the Russian government was behind much of the 'fake news' propaganda that circulated online in the closing weeks of the election," Clinton staffer Marc Elias wrote. "We feel it is important, on principle, to ensure our campaign is legally represented in any court proceedings and represented on the ground in order to monitor the recount process itself."

Trump blasted the recount efforts on Twitter, alleging millions of ballots were cast in the election illegally and suggesting voter fraud in Virginia, New Hampshire and California despite a lack of evidence.

It would be unprecedented for Clinton to take the presidency from Trump, as recounts normally do not yield changes to the results large enough to flip the outcome of an election. A recount has never reversed the result of an American presidential election, though three of 27 recounts since 2000 have awarded reversals in state and local elections (each time to a Democrat).

A group of computer experts noted irregularities in each state where Stein is calling for a recount. The Clinton campaign noted there wasn't any proof of a cyberattack, but if systems were indeed compromised, the recount results could deliver the White House to Clinton. As FiveThirtyEight’s Carl Bialik writes, "hackers could have modified vote totals by more than the usual amount that recounts changed vote totals."

If the results go unchanged, Trump will become president on Jan. 20.