One in four Americans is worried their ballot won't be accurately counted this year, and four in 10 worry mail-in voting could yield less reliable results, according to a new Axios-SurveyMonkey poll.

The big picture: Partisan identification is a massive driver of distrust in both categories — and the stakes are huge this year.

• 42% of respondents overall say they expect to vote by mail amid the coronavirus pandemic, a trend being driven by people under 25 or over 65, women of color, liberal Democrats and independents.
• Seven in 10 Republicans surveyed say mail-in voting is less likely to produce fair and accurate results, while Democrats say on balance they believe it will make the results slightly more fair and accurate.

Why it matters: As President Trump seeks to delegitimize absentee voting and politicize the U.S. Postal Service, the findings in this national survey document the potential for wide voter disenfranchisement or mistrust in the results come November.

• Consider the partisan divide over whether to vote in person or by mail amid the coronavirus pandemic: 80% of conservative or very conservative Republicans say they plan to vote in person, compared with just 33% of liberal or very liberal Democrats.
• Respondents are more likely to prospectively question the validity of the overall results than to doubt that their own vote will be accurately registered.
• But Black and Hispanic respondents were less likely than white respondents to have confidence their own votes will be counted right. People with higher incomes were more likely to trust the process than those who earn less than $50,000 a year.

What they're saying: SurveyMonkey chief research officer Jon Cohen says registered voters are slightly more confident than Americans overall that their own votes will be accurately counted — about eight in 10, although only half of those are "very confident" that will be the case.

• "For Republicans, the lack of trust in the system has shot up," Cohen says. By comparison, he notes, a 2006 Washington Post-ABC News poll ahead of midterm elections found a scant 6% lacked confidence their vote would be counted.

Go deeper: Our survey — which went into the field on Tuesday and Wednesday, beginning after Joe Biden announced Kamala Harris as his running mate — also shows Harris so far accomplishing just what the campaign hoped: doing no harm, while exciting parts of the base with whom Biden needs the most help.

Methodology: This SurveyMonkey online poll was conducted August 11-12, 2020 among a national sample of 2,847 adults (2,558 registered voters) in the U.S. Respondents were selected from more than 2 million people who take surveys on the SurveyMonkey platform each day. The modeled error estimate for this survey is +/- 3.0 percentage points. Data have been weighted for age, race, sex, education, and geography using the Census Bureau’s American Community Survey to reflect the demographic composition of the United States age 18 and over.