Democrats have a fair shot at flipping control of the House — largely because of the boost provided by Vice President Harris at the top of the ticket — but the battle is a horse race that is too close to call heading into the final weeks of the campaign, according to a host of election forecasters following the contest closely. Anecdotally, there were early signs that replacing President Biden with Harris as the nominee over the summer had strengthened the Democrats’ chances of seizing the lower chamber. Lawmakers across the country reported a surge in fundraising, campaign volunteerism and general enthusiasm among base voters that had been lacking with Biden as the candidate.  Almost three months later, outside election experts are pointing to hard data that support those claims, saying Harris has clearly been an overall asset to the Democrats’ downballot prospects.  “More so than anything else, that change in late July and early August has been a real boon to downballot Democrats,” said Jacob Rubashkin, deputy editor at Inside Elections, a nonpartisan election handicapper. “Truly, it’s a rising tide lifts all boats scenario.”  But the Harris effect is not the same everywhere. And there are numerous factors underlying individual races — some cultural, some political, some demographic — that are expected to impact exactly how the Democrats’ newly tapped standard-bearer will sway outcomes in the lower chamber.  A boost among minority voters Election experts say Harris’s influence may reveal itself most dramatically in districts where minority voters could play an outsized role in the contest. Those regions include the Central Valley of California, where Harris is polling better among Hispanics than Biden was, and in areas around New York City, where Black voters now appear ready to turn out in higher numbers than before.  "She has had the most positive impact [for Democrats] in places with large nonwhite populations, which were really dormant in the spring and summer and now are headed for higher turnout than they would have had Biden remained the nominee,” said David Wasserman, senior editor and elections analyst at the Cook Political Report, another nonpartisan election analysis group. Those dynamics have created stronger headwinds for a handful of Republican incumbents who are fending off tough challenges in the Golden State, including Reps. John Duarte, David Valadao and Mike Garcia, all of whom are in toss-up races in districts with significant Hispanic populations. In New York, a similar trend has emerged in contested races on Long Island and in Westchester County. There, Harris’s presence is expected to energize Black voters, lending a boost to the Democrats challenging first-term GOP Reps. Anthony D’Esposito and Mike Lawler. Wasserman said the change has “probably made” D’Esposito’s challenger, Laura Gillen, the favorite in the race, while keeping former Rep. Mondaire Jones, the Democrat vying to unseat Lawler, “in contention” to flip the seat. Harris is also giving Democrats new pickup opportunities in Midwestern districts surrounding small cities like Omaha, Neb., where Rep. Don Bacon (R) is fighting for his political life, and Des Moines, Iowa, where Reps. Zach Nunn (R) and Mariannette Miller-Meeks (R) were the favorites with Biden on the ticket but are now facing rockier roads to reelection under Harris.  “We're noticing in midsized Midwestern cities Harris is performing quite well,” Wasserman said. “Her margin appears to be ahead of where Biden's was in 2020, and that has helped Democrats in those toss-up House contests.” Disagreement over Pennsylvania While election forecasters broadly agree that Harris’s ascension to the top of the presidential ticket has been a benefit for Democrats, there’s a debate underway about whether she is a drag on downballot Democrats in northeast Pennsylvania — particularly the Scranton area, where Biden was born and grew up. The discussion has been focused on Pennsylvania’s 7th Congressional District, represented by Rep. Susan Wild (D), and the neighboring 8th District, led by Rep. Matt Cartwright (D). Both are rated toss-up races by Cook Political Report, and Biden narrowly captured both districts in 2020. Zachary Donnini, a data scientist at Decision Desk HQ, another nonpartisan election handicapper, pointed to those two districts as places where Biden could have helped House candidates more than Harris is now. Donnini cited Biden’s popularity in his hometown of Scranton — “people call him Scranton Joe” — and noted that the president performed well in the pair of districts in 2020. “If you run a regression and look at how you would have expected a generic Democrat to perform in the Lehigh Valley and the Delaware Valley and Scranton and Allentown, Bethlehem in 2020, Biden vastly overperformed expectations,” Donnini said. “The home region boost is real for him and it would’ve been again in 2024.” That argument, however, is a point of contention. Rubashkin, for example, said that while there is “some mystique” around the Scranton area because of Biden’s roots, he concluded “I don’t buy that.” Wasserman, similarly, said Harris is not running too far behind the president in “the Biden Belt of Pennsylvania,” and said the candidate appears to be faring well among a key constituency in that area. “The big question mark is: Can she match Biden's numbers among working-class white voters?” Wasserman said. “Her polling shows her about on par with Biden. But past years' polls have overestimated Democrats' with that demographic." Helping Democratic incumbents Still, the forecasters are all in agreement that Harris’s ascension has been an overwhelming benefit to her party overall. And that’s true not only for those challenging sitting Republicans, but also for Democratic incumbents, who have seen their prospects improve after the roster change at the top of the ticket. In Nevada, for example, Rubashkin of Inside Elections said reelection races for Democratic Reps. Steven Horsford, Susie Lee and Dina Titus would have been closer if Biden remained at the top of the ticket rather than Harris. He argued that Harris’s elevated performance in the Silver State, as compared to that of Biden, is helping “secure” those key Democratic districts. “If Biden was gonna lose Nevada by 7 points, then Dina Titus would not be in [the] ‘solid Democratic’ [column]; Steven Horsford and Susie Lee would not be in ‘likely democratic,’ they would be in the political fights of their lives,” Rubashkin said. “But because Harris has fought Nevada to a draw or maybe a slight lead, those districts look a lot more secure.” On Thursday, Inside Elections moved Titus’s race in Nevada’s 1st Congressional District from likely to solid Democratic. Election experts say it’s not only the figure of Harris — a generation younger than Biden and the first Black woman ever to secure a major party nomination — that’s given Democrats a push in the final months of the campaign. She’s also adopted a message designed to distance herself from the more controversial policies of the Biden administration in which she currently serves. That, in turn, has empowered other Democrats in tough races to do the same.  “She's still behind on immigration and the economy, but she has taken a diametrically opposite approach to Biden when it comes to messaging on the economy, because she's been much more future oriented, rather than trying to sell voters on the record of the administration,” Wasserman said. “And that has allowed more Democrats to run on their own biographies, rather than defend every action the administration has taken." Republican campaign operatives have acknowledged the new challenges they face in running against Harris versus Biden, not least the burden they face in recalibrating their messaging toward a brand-new target just months before Election Day.  Still, they also see Harris as an easier target, in some respects, because of liberal positions she’s taken in the past, including support for a fracking ban and the “defund the police” movement. They’re bullish about their chances of keeping control of the House, and their message leans heavily on tying House Democrats — and Harris — to Biden’s track record. "The choice is clear: four more years of an unaffordable cost of living and a weakening job market or a return to the prosperity Americans enjoyed prior to 2020,” Will Reinert, spokesperson for the House Republicans' campaign arm, said Friday. Which message prevails, of course, will be up to voters on Nov. 5. Heading into Election Day, the handicappers say control of the lower chamber — and White House — remain up for grabs, with polls showing the races neck and neck. But with Harris at the top of the ticket instead of Biden, some forecasters say even if Harris loses, her support could help bring in a Democratic House majority. “If Harris narrowly loses the Electoral College, Democrats can still win the House because she’ll have lost by a little bit,” Donnini of Decision Desk HQ said. “If Biden would’ve lost it, it probably would’ve been by a lot, and it probably would’ve completely killed Democrats’ chance to get a majority in the House.”