Democrats are mounting their most extensive voter protection effort ever to gird for what Joe Biden called his biggest fear: the prospect that US President Donald Trump will try to interfere with the November 3 election, or refuse to accept its outcome.
Interviews with more than a dozen party officials reveal how Democrats, in coordination with Mr Biden's presidential campaign, are preparing for fights over absentee ballots, potential voting recounts and the possibility that Trump's Republican supporters will seek to intimidate voters at the polls.
The Democratic Party has hired voter protection directors in 19 key states to lead more comprehensive operations than in past cycles and filed a record number of lawsuits ahead of the election trying to make voting easier.
Thousands of election monitors and lawyers will be mobilised across the country on election day, the officials told Reuters.
Republicans say that while they are making routine preparations for recounts and voting irregularities, they are more focused on combating efforts to expand mail-in balloting.
Mr Trump has cast doubt on the legitimacy of mail-in ballots, which have been used in far greater numbers in primary elections amid the coronavirus pandemic. He has also made unsubstantiated allegations that voting will be rigged and has refused to say he would accept official election results if he lost.
A person briefed by the Biden campaign on its strategy told Reuters that the former vice president's staff was bracing for a "nightmare scenario" in which Mr Trump is leading the in-person vote count in battleground states on election night but complains the contest is being stolen from him in ensuing days as mail-in ballots get counted.
One party official in a battleground state who asked not to be identified said the campaign was quietly coordinating a legal strategy with state-level party staff for post-election scenarios such as the 2000-style Bush-Gore recount.
Mr Trump is "laying the groundwork to say: 'The election was stolen, there was fraud, we're going to go to court, we're going to call out people on the streets,'" said Mark Brewer, an elections lawyer who is helping train Democratic legal volunteers in Michigan.
"The guy is capable of anything, so we have to plan for everything."
Trump campaign spokesman Tim Murtaugh said Democrats were trying to undermine the election's integrity with efforts that could lead to fraud.
"In a free and fair election, President Trump will win," Mr Murtaugh said.
The state-level Democratic official said Bob Bauer, a former Obama administration counsel now active in the Biden campaign, and Marc Elias, a leading voting rights and recount attorney, were "part of the contingency planning". Mr Bauer and Mr Elias did not respond to interview requests.
Democrats say their greatest focus is on guarding against what they expect to be a significant voter-suppression effort.
Party officials in Michigan, Wisconsin and Pennsylvania - where Mr Trump won narrowly in 2016 and that Biden now leads - are planning robust poll-watching efforts.
Democrats say increased emphasis on poll monitoring is fuelled by uncertainty over Michigan's new rules that allow every voter to cast a ballot by mail, which Mr Trump opposes, as well as the expiration of a 1982 decree designed to stop Republicans from suppressing votes.