Control of the US House is up for grabs – and may hinge on two blue states

California and New York are reliably Democratic – so no suspense there for Tuesday’s election, right?

Wrong. These two states may well determine control of the U.S. House of Representatives, where Republicans currently hold a whisker-thin majority. If Democrats can flip just four seats, they will retake control. And California and New York have more swing districts than anywhere else – including many GOP-held seats in districts Joe Biden won in 2020. Between them, they may well determine whether the House acts as a brake or gas pedal for the next president.

In this era of tight margins, it’s not a given that Democrats will get what they need in these blue bastions. And even if they do, the gains could be canceled out in other states where Republicans are trying to flip seats, such as Pennsylvania, Michigan, Alaska, and Maine.

“The fight for the House is as close as the fight for the presidency, and I don’t think either party has a clear advantage in either one of those races,” says Nathan Gonzales, editor and publisher of the nonpartisan Inside Elections.

With partisan gerrymandering greatly reducing the number of competitive districts across the United States, Mr. Gonzales’ nationwide rankings list just 15 pure toss-ups, five of which are in New York and California. Four more seats in those states are rated as competitive, but slightly favoring either Democrats or Republicans.

The coattail effect

House races are notoriously hard to poll. And in an era of nationalized politics, the top of the ticket in a presidential year can have a huge impact. Democrats feel they got a reprieve when President Biden dropped out of the race last summer and Vice President Kamala Harris became the nominee. They’re hoping she’ll draw more voters to the polls, and that those voters will pick Democrats all the way down the ballot.

California is Ms. Harris’ home state, and she has support from 59% of voters there. That strength could be the difference in competitive districts like CA-13 in the agricultural Central Valley, where Republican Rep. John Duarte beat his Democrat opponent by a mere 564 votes in 2022. Similarly, Republican Rep. Mike Garcia eked out a win in CA-27, in northern Los Angeles County, by 333 votes in 2020.

On Sunday, Mr. Garcia’s Democratic opponent, George Whitesides, rallied volunteers for a home-stretch push at a park in Santa Clarita, a northern suburb of Los Angeles. The district’s lines were redrawn after the last census, and Democrats now outnumber Republicans there. Still, “Trump trains” of pickup trucks and flags run regularly through this part of the Mojave high desert, home to a state prison and Edwards Air Force Base. The heavily Latino district has thrice elected Mr. Garcia, a decorated Navy combat pilot and former Raytheon executive.

Mr. Whitesides, who is running as a moderate Democrat, has an aerospace background as the former CEO of the Mojave-based space tourism company Virgin Galactic and a former chief of staff of NASA. His wife is Cuban and Salvadoran. He boasts of having created 700 local jobs – an important consideration for commuters to Los Angeles, who battle two-hour drives each way, high gas prices, and higher housing costs as more people move from LA to the exurbs.

The Garcia campaign is attacking Mr. Whitesides for his political donations, including to unpopular progressive LA County District Attorney George Gascón and the LGBTQ+ advocacy group Equality California. The group supported a bill equalizing sentencing for sex crimes; an attack ad accuses Mr. Whitesides of having “funded a group opposing pedophiles registering as sex offenders.”

The Whitesides campaign is hitting Mr. Garcia for his votes against the bipartisan infrastructure bill and against the bill that included a price cap on insulin for older adults, and for rejecting the electoral count for Mr. Biden in 2020. And they’ve hammered the congressman for his “no exceptions” opposition to abortion, though in a statement Mr. Garcia says he does support exceptions for rape, incest, and the life of the mother.

In an interview, Mr. Whitesides said, “Choice is obviously a huge deal” that cuts across demographic groups and parties. Even though the California Constitution protects reproductive rights, voters are worried about a national ban and concerned for women in other states, he says. With polls showing his campaign ahead by 2 points, he says he feels “cautiously positive.”

A 2022 drubbing for New York Democrats

On the other side of the country, in New York, Democrats have high hopes for retaking the seat held by Rep. Brandon Williams, a first-term Republican who represents Syracuse. In 2022, the former Navy submarine officer defeated his Democrat opponent by less than 1 percentage point, and his all-in stance for Donald Trump puts him at odds with his redrawn district, which shifted from Biden+7 to Biden+11.

Democrats are aggressively going after three more New York seats, and eyeing a “cherry on top” at the tip of Long Island, says Jacob Smith, an assistant professor of political science at Fordham University.

In the 2022 midterms, held not long after the Supreme Court overturned Roe v. Wade, Democrats did better than expected nationwide, with an anticipated “red wave” largely failing to materialize. But in the Empire State, the party got swamped, says Professor Smith.

That drubbing in New York, however, now means Democrats have an opportunity to win back those seats. Professor Smith points to an October poll by Siena College that shows Ms. Harris leading Mr. Trump by 19 points among likely voters in the state – a big jump from September, when she led by 13 points. If the trend holds, “That sort of a rising tide lifts all boats,” he says.

On the other hand, in California, state GOP Chairwoman Jessica Millan Patterson lists lots of reasons she believes “The environment is fantastic for us.” Mr. Trump may be polling at only 33% in the state – but that’s little changed from 2020, when Republicans picked up four House seats there. Before that, they hadn’t flipped a seat from blue to red in California since 1994. They gained another in 2022.

Republican registrations overall in California have been rising, after years of decline. Ms. Patterson notes that since she took over party leadership in 2019, it has registered more than 820,000 new Republicans.

Party investments in community centers that serve Latinos and Asians in swing districts have made a “huge” difference, she says, noting that Representative Garcia gained 18 points among Latinos from 2020-2022 after the GOP created a community center in his district. The party saw a similar shift in Republican Rep. David Valadao’s Central Valley district, CA-22, where it has another Latino center. Ms. Patterson, herself Latina, says Latino voters “are the pathway back to sanity” in the state.

The independent Cook Political Report notes that Democrats are showing signs of slippage overall in California, with Ms. Harris running 6 points behind Mr. Biden’s 2020 vote share in a recent poll. And that slippage appears to be driven largely by Latinos. While Mr. Biden won that group by nearly 40 points in 2020, the vice president is currently winning them by only 20.

Republicans have an easy explanation for all of this – persistent problems with homelessness, border security, affordability, and crime. “California Democrats have destroyed the Golden State,” says Ms. Patterson, pointing to high levels of support in polls for Proposition 36, which would increase punishment for certain drug and theft crimes.

Crime is something Scott Baugh hears a lot about when he knocks on doors. The Republican former state legislator is running for the open seat vacated by Democrat Katie Porter in Orange County – where seats have flipped back and forth between parties. This district, CA-47, has been reconfigured and is rated by most election analysts as a toss-up or lean Democrat. But Mr. Baugh is ahead of his challenger, Democratic state Sen. Dave Min, by at least 3 points in some polls.

“People are uniting around the constant stories about crime,” says Mr. Baugh in an interview at a rally in Newport Beach on Saturday. Many voters here were shaken by a murder during a botched robbery outside the city’s upscale Fashion Island mall this summer, followed a month later by another robbery and shooting there. “All of our Orange County Republicans are going to get reelected. I’m going to be elected. Even Democrats know that,” says Mr. Baugh, on a morning thick with marine fog. “We will maintain the House [majority] and grow it,” he says with confidence.

With polls that lie within the margin of error, no one will know until after Election Day. Even then, it could be weeks before the outcome is clear, because of the heavy use of mail-in ballots in California and the time it takes to count them.