In a sign of her post-debate strength, Vice President Harris is closing the gap with President Trump in ruby red Iowa — a state she is unlikely to win in November, but could help deliver a House majority for Congressman Hakeem Jeffries. The state was won twice by Trump in 2016 and 2020, and has been considered out of reach for Democrats at the presidential level this year. 

According to a new Des Moines Register poll, Ms. Harris trails the former president by just four points — 47 percent to 43 percent. In June, Trump had an 18-point lead over President Biden in the Hawkeye State.

“I wouldn’t say 4 points is comfortable” for the 45th president, said the Des Moines Register’s pollster, J. Ann Selzer. “The race has tightened significantly.”  

“This poll may be catching newly energized voters who thought they would sit out the election at the time our June poll was taken,” Ms. Selzer said. 

Trump won the state by wide margins in 2016 and 2020. He beat Secretary Clinton by nearly 10 points eight years ago, and won the state with 53 percent of the vote in 2020 — nine points more than Mr. Biden. 

Iowa was last won by a Democrat in 2012, when President Obama carried the state with nearly 52 percent of the vote. All four of the state’s congressional districts are represented by Republicans, and the same is true of Iowa’s two Senate seats. 

Iowa was considered a potential reach state for Mr. Biden in 2020, with polling that showed Trump leading by single-digits in the state just days before the election. That same year, a Democratic candidate for the Senate — Theresa Greenfield — was able to raise more than $55 million for her campaign, though she too came up short. 

The Des Moines Register poll — considered one of the most accurate in American political polling — shows that independent candidate Robert F. Kennedy Jr. is still taking six percent of the vote among likely voters, despite the fact that he dropped out of the race and endorsed Trump in August. Just one percent of voters say they would vote for someone other than Trump, Ms. Harris, or Mr. Kennedy. 

Trump’s strength in Iowa comes mostly from male voters. An overwhelming majority — 59 percent — of Iowa men prefer Trump, compared to just 32 percent who plan to vote for Ms. Harris. Among women, Ms. Harris’s lead is less commanding. Just 53 percent of Iowa women plan to vote for the Democratic candidate, while 36 percent say they will vote for Trump. 

The former president’s base of support seems to be softer than Ms. Harris’s, however. Among likely voters who say they plan to vote for Trump, 16 percent say they could still be persuaded, while just 11 percent of likely voters who plan to vote for Ms. Harris say they could change their vote before November. 

Both candidates are seeing relatively high levels of enthusiasm among their respective partisan bases. For those who list Ms. Harris as their first choice, 34 percent say they are “extremely enthusiastic,” 46 percent say they are “very enthusiastic,” and 18 percent say they are “mildly enthusiastic.” For Trump, among the voters who list him as their first choice, 33 percent say they are “extremely enthusiastic,” 40 percent say they are “very enthusiastic,” and 22 percent say they are “mildly enthusiastic.”

For years, Iowa was considered the Midwestern bellwether state, though that title has now shifted to Pennsylvania. Ms. Harris’s choice of Minnesota’s governor, Tim Walz, as her running mate, may have boosted her standing among heartland voters.