The US President Donald Trump and his Democratic rival Joe Biden have made a last-ditch push for votes in battleground a state on the last day of campaigning, as each party prepares for post-election disputes that could prolong a divisive presidential election.
Trump is trailing in national opinion polls and has continued to lob unfounded attacks at mail-in ballots, suggesting he would deploy lawyers if states are still counting the votes after Election Day on Tuesday.
Trump told reporters that Pennsylvania's plans to count mail ballots that arrive up to three days after Election Day would lead to widespread cheating, although he did not explain how.
He urged the US Supreme Court to reconsider its decision that left the extension in place. The court has left that possibility open.
Bad things will happen and bad things lead to other type things, he told reporters in Wisconsin, another battleground state.
On Twitter, Trump said the court decision would induce violence in the streets. The social media platform flagged his message, adding a disclaimer to the tweet that its content was disputed and might be misleading.
It's not unusual for US states to take several days or even weeks to count their votes, and a record surge in mail ballots could draw out the process further this year.
Under no scenario will Donald Trump be declared a victor on election night, Biden campaign manager Jennifer O'Malley Dillon told reporters.
The election has prompted an unprecedented wave of litigation over whether to adjust voting rules in light of the Covid-19 pandemic.
Both sides have amassed armies of lawyers who are prepared to take on post-election battles.
On Monday, a federal judge in Texas rejected a Republican bid to throw out about 127,000 votes already cast at drive-through voting sites in the Democratic-leaning Houston area.
In Pittsburgh, Biden told supporters the country's future rested in their hands.
When America votes, America is heard. And when America is heard, the message will be out loud and clear: it's time for Donald Trump to pack his bags and go home, he said.
Trump, 74, is seeking to avoid becoming the first incumbent president to lose re-election since fellow Republican George H.W. Bush in 1992.
Despite Biden's overall national polling lead, the race in swing states is seen as close enough that Trump could still piece together the 270 votes needed to prevail in the state-by-state Electoral College system that determines the winner.
Trump has spent the final days of the campaign predicting victory and deriding Biden for backing restrictions that aim to slow the spread of the coronavirus.
A vote for Biden is a vote for lockdown, misery and layoffs, he told the crowd in Scranton, Pennsylvania.
Many Democrats said they were nervous about the results after expecting Trump to lose handily in 2016.
Obama, whom Biden served as vice president for eight years, said Trump's push to stop counting votes on election night was undemocratic.
That's what a two-bit dictator does, he told a rally in Miami. If you believe in democracy, you want every vote counted.
After visits to North Carolina and Pennsylvania, Trump headed to Wisconsin and Michigan. He narrowly won those four states in 2016, but that polls show they could swing to Biden this year.
As he has done for months, the president spoke to large crowds, where many attendees eschewed masks and social distancing despite the resurgent Covid-19 pandemic.
Biden, 77, who has made Trump's handling of the pandemic the central theme of his campaign, spoke in Ohio and Pennsylvania to much smaller gatherings.
The latest Reuters/Ipsos poll in Florida, a perennial swing state, showed Biden with a 50-46 percent lead, a week after the two were in a statistical tie.
Early voting has surged to levels never before seen in US elections. A record-setting 98.4 million early votes have been cast either in person or by mail, according to the US Elections Project.
The number is equal to 71.4 percent of the entire voter turnout for the 2016 election and represents about 40 percent of all Americans legally eligible to vote.
That unprecedented level of early voting includes 60 million mail-in ballots that could take days or weeks to be counted in some states, meaning a winner might not be declared in the hours after polls close on Tuesday night.