More than four in ten supporters of both President Donald Trump and his Democratic challenger, Joe Biden, said they would not accept the result of the November election if their preferred candidate loses, Reuters/Ipsos poll found.
The survey, conducted from Oct. 13-20, shows 43 percent of Biden supporters would not accept a Trump victory, while 41 percent of Americans who want to re-elect Trump would not accept a win by Biden.
Smaller portions would take action to make their displeasure known: 22 percent of Biden supporters and 16 percent of Trump supporters said they would engage in street protests or even violence if their preferred candidate loses.
US election officials are dealing with a series of challenges this year that have raised concerns about the public's confidence in the result.
Top national security officials warned last week that Russia and Iran have been hacking into US voting systems and looking for ways to undermine the election.
Trump also has repeatedly questioned the integrity of US elections, arguing that the process is "rigged" against him and repeatedly asserting without evidence that the surge in mail-in voting this year will increase the likelihood of voter fraud. He has refused to commit to a peaceful transfer of power if the vote count indicates he has lost.
Donald Green, a political scientist at Columbia University, said the poll results ease his concerns about post-election violence. But he warned that if the election is close, or one candidate can make a credible accusation of voter fraud, it could spark wider discontent and protests than the poll suggests.
"This is why many people who oppose Trump are holding their breath and hoping for a lopsided outcome that is not up for grabs," Green said.
The latest Reuters/Ipsos poll shows Biden leads Trump by 8 percentage points nationally: 51% of likely voters say they are backing the Democratic challenger while 43% are voting for the president.
Biden also is ahead in Wisconsin and Michigan, but the race appears to be much closer in other battleground states including Pennsylvania, Florida, Arizona and North Carolina.
The Reuters/Ipsos poll was conducted online, in English, throughout the United States. It gathered responses from 2,649 American adults, including 1,039 who said they had voted for Trump or were planning to vote for him, and 1,153 who said they were similarly backing Biden.
The poll has a credibility interval, a measure of precision, of 4 percentage points.