BERKELEY (CBS SF) — A large portion of California voters worry that other Americans won’t respect the results of the Nov. 3 presidential election and could inflict violence, a survey conducted by UC Berkeley’s Institute of Governmental Studies (IGS) found.

The legitimacy of the election and the post-election aftermath were big issues among the over 6,600 poll respondents. In all, 87% of voters expressed worry that other voters would dispute the outcome, and 88% said violence is somewhat or very likely in such an event.

The survey also found that 40% of likely voters in Berkeley who responded doubt the election will be conducted fairly. That sentiment appeared especially strong among local supporters of President Donald Trump, with 56% of them questioning the fairness of the election and 78% expressing little confidence in voting by mail.

“The lack of public confidence that all votes will be counted and that both parties will respect the election outcome are worrisome signs of a political system that is under unusual stress,” IGS co-director Eric Schickler said.

Also, 53% of Trump-supporting respondents felt that violence was “very likely” in a situation, opposed to only 40% of Joe Biden supporters. The majority of respondents aged 18-29, 54%, said they expected violence, while that percentage dropped as the demographic’s age went up.

The IGS administered the poll online in English and Spanish between Oct. 16 and 21, 2020, surveying 6,686 registered voters in California, 5,352 of whom were considered likely to vote or had already voted in this year’s election. The margin of error was plus or minus two percentage points.

Learn more about the poll at the IGS website.