Joseph R. Biden Jr. has a narrow lead over President Trump in Iowa, a state Mr. Trump carried by more than nine percentage points in 2016, and the high-stakes Senate race there appears even closer, according to a New York Times/Siena College poll released Wednesday.
Mr. Biden leads Mr. Trump 46 percent to 43 percent among likely voters in Iowa, with 7 percent saying they were undecided or refusing to name a preference, according to the survey.
Senator Joni Ernst, a Republican whose re-election race could help determine control of the Senate, is capturing 45 percent support while Theresa Greenfield, her Democratic opponent, has 44 percent.
Mr. Biden, the former vice president, is being propelled by women, younger voters and white voters with college degrees, the same demographics lifting him across the country. Yet he is also running stronger in Iowa among seniors and working-class white voters than he is in other similarly Republican-leaning states.
Mr. Biden is leading among voters 65 and older, 49 percent to 42 percent, and he is trailing Mr. Trump among white voters without college degrees by only seven points, 48 percent to 41 percent.
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The poll, which interviewed 753 likely voters in Iowa by phone from Oct. 18 to 20, has a margin of sampling error of about four percentage points.
Iowa’s increasing competitiveness was made clear last week, when Mr. Trump returned to the state for the first time since the start of the year and held a rally at the Des Moines airport. Mr. Biden has not appeared in the state since the Democratic caucuses in February.
That Mr. Biden has an opportunity to contest Iowa at all is striking given its recent political tilt. After former President Barack Obama carried it twice, the state swung decisively to Mr. Trump in 2016, and a well-funded Democratic candidate for governor fell short two years later.
Yet as in other Midwestern states, Mr. Trump’s incendiary conduct has alienated many voters and nudged them back to their Democratic roots. The president is viewed unfavorably by more than half of likely Iowa voters, and very unfavorably by over half of women and college-educated voters there.
Charissa Frangione, 34, a small-business owner and City Council member in Marcus, Iowa, voted for Mr. Trump four years ago but said she had soured on him since then. In 2016, “I just thought, who better to get the economy back in order than a businessman?” she said.
Oct. 21, 2020, 4:15 p.m. ET
“Unfortunately, I just don’t feel like he’s lived up to my expectations as a president,” Ms. Frangione said. “Even the good things he does are washed out by his demeanor.” She has already voted by mail for Mr. Biden.
Unlike Hillary Clinton, who was as unpopular as Mr. Trump in surveys leading up to the 2016 election, Mr. Biden is not as polarizing a figure as the president: Fewer than half of the poll’s respondents viewed him unfavorably. And while 47 percent of independent voters had a very unfavorable view of Mr. Trump, just 27 percent of independents felt the same animus toward Mr. Biden.
While Mr. Biden may not ultimately need Iowa’s six electoral votes to claim the presidency, the state could prove more pivotal in the battle for the Senate. Should Mr. Biden be elected, Democrats would need to gain three seats to win control of the chamber. And few Senate races appear as closely contested as the one in Iowa, where outside groups are saturating the airwaves on behalf of both candidates.
Ms. Ernst was one of the breakout winners of the 2014 midterm elections, memorably airing an ad recalling her youthful days castrating hogs and promising to cut the pork in Washington. But she has proved vulnerable this year.
She is plainly suffering from Mr. Trump’s divisiveness, as made clear by her deficits among women and college-educated white voters in the poll, but she does not enjoy the president’s intensity of support from Iowa Republicans. While 73 percent of them have a very favorable view of Mr. Trump, only 57 percent feel the same way about Ms. Ernst.
Ms. Greenfield, a businesswoman and first-time candidate, has benefited from not being very well defined. While 47 percent of Iowans in the survey held an unfavorable view of Ms. Ernst, just 38 percent said the same about Ms. Greenfield.
Yet Ms. Ernst is running stronger than Mr. Trump in part because she is more palatable to independent voters. While Mr. Trump is trailing with these unaffiliated Iowans by 17 points, Ms. Ernst is only down by seven with the same group. Similarly, while Mr. Trump trails among seniors, Ms. Ernst and Ms. Greenfield are tied among older voters.
Both the presidential contest and the Senate campaign remain fluid: Over 10 percent of likely voters in each race said they were undecided or voting for a third-party candidate, or did not want to say whom they were voting for.
Here are the crosstabs for the poll.
Isabella Grullón Paz contributed reporting.