With around three weeks to election day, pollsters are finding a tightening race between Vice President Harris and President Trump as Ms. Harris’s honeymoon phase appears to be coming to an end and Trump is gaining ground with non-white voters. The gender gap, too, could be decisive across the seven core battleground states. 

Over the weekend, a number of highly rated pollsters released surveys showing a close race. For weeks, Ms. Harris held a steady lead in national polls thanks mostly to her support from women and college-educated voters. As that gap widens, Trump is solidifying his support among men and those voters without a college degree. 

A NBC News poll released on Sunday shows a dead heat, with both candidates taking 48 percent of the vote. A widening gender gap is powering that result. Trump leads Ms. Harris among men by 16 points, 56 percent to 40 percent, as Ms. Harris opens a 14-point lead over Trump, 55 percent to 41 percent. 

If that polling bears out, it would be the largest gender gap for presidential vote preference in American history, according to the Center for American Women and Politics. 

The education divide is also solidifying both candidates’ strengths in the sprint to November 5. Ms. Harris is opening a lead among white voters with college degrees or higher, winning them by a margin of 14 points, while losing white voters without college degrees by 32 points to Trump. 

As Ms. Harris makes strong gains with women and college-educated voters, she is failing to win the requisite support of critical voting blocs that have long swung Democratic — Hispanic and Black voters, especially those that don’t have a college degree. 

A poll from the New York Times and Siena College on Saturday found Ms. Harris running far behind previous Democratic nominees’ margins with Hispanic and Black Americans, so much so that it could risk Ms. Harris losing battleground states like Michigan, Georgia, Arizona, and Nevada. 

The Times–Siena survey found Ms. Harris winning Hispanic voters by just 19 points over Trump, which would seem like a landslide if not for the fact that Secretary Clinton and President Biden had much larger victories among the demographic. Mrs. Clinton won Latinos by 39 points in 2016, while Mr. Biden won them by 26 percent in 2020. President Obama won more than 70 percent of the Hispanic vote in 2012. 

Ms. Harris seems to be aware of the problem, as she has leaned into Spanish-language media in recent days. During a Univision town hall on Thursday, she talked about her “opportunity economy” and her plans to bring down the cost of living, while also leaning into tougher rhetoric on immigration and border security measures. 

The Times’s top polling analyst, Nate Cohn, explains that Black and Hispanic voters — most notably, men — have embraced some of Trump’s core governing principles in recent years, amid two wars, a crisis of affordability, and an historic number of migrant crossings at the southern border. 

“The support for Mr. Trump’s views extends beyond issues related to race and immigration. A majority of Black and Hispanic voters seem to sympathize with his ‘America First’ foreign policy, saying that America ought to pay less attention to problems overseas and concentrate on problems at home. Previous Times/Siena surveys have found that a substantial share of Black and Hispanic voters agree with Mr. Trump on trade as well,” Mr. Cohn writes. 

“Or put differently: There’s a lot about Mr. Trump’s core populist, conservative message that resonates with a sizable chunk of Black and Hispanic voters,” Mr. Cohn ventures. 

The vice president is scheduled to go on a tour of several swing states in the coming days, as she and her running mate, Governor Walz, try to close the deal with voters. On Sunday, she’ll rally in North Carolina with supporters before spending Monday through Saturday traveling to Pennsylvania, Michigan, Wisconsin, and Georgia. Mr. Walz will do his own events in western Pennsylvania, Wisconsin, and Nebraska, where one Electoral College vote is up for grabs.