Trump’s falsehoods — and what Democrats say is the threat he poses to democracy — have even some Democrats questioning whether their party should accept a loss in the Nov. 5 election.
While 19% of Republicans say Trump should reject the election results if he loses, 12% of Democrats say Kamala Harris should do the same if she loses.
Actually have some good news here. If you look at the survey itself, it explains that this was part of the question,
In other words, that 19% is assuming that he’ll declare it stolen.
Source: https://www.prri.org/research/challenges-to-democracy-the-2024-election-in-focus-findings-from-the-2024-american-values-survey/#page-section-8