US President Donald Trump sparked a furore suggesting he might not accept the results of the November 3 election if he loses.
His stance drew comparisons with lawless dictators -- Belarus and North Korea were mentioned -- and raised fears that he could fracture the US democratic system in a cling to power.
Trailing Democratic rival Joe Biden in polls, the US leader refused to rule out the prospect on Wednesday when asked if he would support a peaceful transition.
"Well, we're going to have to see what happens," he replied.
Trump has already prepared the ground should he decide to challenge the results, repeatedly claiming that Democrats will hijack tens of millions of mailed-in ballots to defraud the vote.
"Democrats are rigging our 2020 Election!" he declared Thursday after a handful of early mailed ballots marked for Trump were discovered discarded in a Pennsylvania election office.
In most recent US elections, winners have been declared, and losers have conceded, within hours of the polls closing in November, based on the early vote counts.
When the loser concedes, it allows the winner to immediately begin preparing to take power in January, well before the official winner is declared by the Electoral College in mid-December.
This year experts agree with Trump on one key point: because of a massive surge in voting by mail due to the coronavirus, and untested systems for handling those votes, early election results might be very incomplete and open to challenge.
The winner "likely will not be known on election night," concluded the Transition Integrity Project, a group of academics and former government officials studying possible 2020 problems.
TIP, whose members include both Democrats and Republicans, says it expects a period of legal and political "chaos", exploitable by the parties.
Unless Biden captures the election by a clear landslide, TIP expects Trump to exploit any ambiguity, laws and his presidential powers, to assert victory and refuse to leave office.
"We also assess that President Trump is likely to contest the result by both legal and extra-legal means, in an attempt to hold onto power," they said.
First, if the projected results on election night go against him, he will refuse to concede and challenge the vote count, with the support of Republican political operatives on the ground in the states.
That could lead to grinding recounts, with each ballot reviewed and challenged on any anomaly: a smudged signature, an abbreviated address, or a ballot mailed without a special inner envelope meant to ensure secrecy -- which in some cases can lead to its rejection as a "naked ballot."
On the other hand, if Trump sees himself leading the night of November 3, he could declare victory before millions of mailed ballots are tallied.
Analysts believe that more Democrats will vote by mail than Republicans, and Trump has already suggested he may not accept their validity.
"The ballots are out of control," Trump said Wednesday. "Get rid of the ballots and you will have a very peaceful -- there won't be a transfer, frankly. There will be a continuation," he said.
In the 2000 presidential election, the fight between Democrat Al Gore and Republican George W. Bush came down to the result in one state, Florida.
The state's Republican-controlled government declared Bush the winner on a miniscule vote margin. Gore's side went to court for a recount of millions of "punch-card" ballots which proved prone to errors and miscounting.
The case escalated to the Supreme Court, which ruled against a recount, handing the election to Bush.
This year Trump's Republicans are preparing to challenge adverse results in a number of key states like Florida, Wisconsin, Michigan and Pennsylvania.
"There is a chance the president will attempt to convince legislatures and/or governors to take actions -- including illegal actions -- to defy the popular vote," said TIP.
"A determined campaign has the opportunity to contest the election into January 2021," it said.
The Republican Senate leader Mitch McConnell -- whose body could remove Trump by impeachment if he refuses to go -- sought to reassure voters this week.
"The winner of the November 3rd election will be inaugurated on January 20th," he said.
