ROCKVILLE CENTRE, N.Y. — A year ago, Republicans staged an uprising in the Long Island suburbs, winning a slew of races by zeroing in on public safety and suggesting that Democrats had allowed violent crime to fester.Now, with the midterms approaching, Democratic leaders are hoping that their own singular message, focused on abortion, might have a similar effect.“Young ladies, your rights are on the line,” Laura Gillen, a Democrat running for Congress in Nassau County, said to two young women commuting toward the city on a recent weekday morning. “Please vote!”Long Island has emerged as an unlikely battleground in the bitter fight for control of the House of Representatives, with both Democrats and Republicans gearing up to pour large sums of money into the contests here.Nassau and Suffolk Counties, where nearly three million New Yorkers live, have become a powerful testing ground for the main campaign themes of each party, with Democrats hoping that their renewed focus on abortion rights — following the recent Supreme Court decision that overturned Roe v. Wade — will help them retain control of the House.The New York City suburbs are at a rare political crossroads: Three of the four House seats that encompass most of Long Island are open this year after their incumbents retired or stepped aside to seek higher political office, offering both parties a unique, regionally concentrated opportunity to send new faces to Congress.The two districts that are mostly situated in Nassau County, just east of Queens, are held by Democrats, while the two districts concentrated on the eastern stretch of the island in Suffolk County are held by Republicans. Both parties are vying to gain one, if not, two seats.That prospect has injected a sense of urgency and uncertainty into the races on Long Island, once a Republican stronghold that has turned more Democratic and diverse in recent decades, becoming the type of suburban swing area that could determine control of the House in November.Republicans have almost exclusively focused on blaming Democrats for rising prices as well as on public safety: They have amplified concerns about the state’s contentious bail laws and crime in nearby New York City, where many Long Islanders commute for work.“Many Democrats feel like that they don’t have a party anymore because it’s gone so far to the left,” said Anthony D’Esposito, a former New York City police detective and local councilman running against Ms. Gillen, the former Town of Hempstead supervisor who lost her seat in 2019. He suggested that police officers, firefighters and emergency medical workers who live in Nassau County but work in the five boroughs are alarmed by crime in the city.Anthony D’Esposito, a former New York City police detective, is trying to flip a Democratic seat being vacated by Kathleen Rice.Johnny Milano for The New York TimesMr. D’Esposito and Ms. Gillen are running in a tight race to replace Representative Kathleen Rice, a Democrat who announced in February that she would not run for re-election in the Fourth District in central and southern Nassau, which she has represented since 2015.“The Dobbs decision was a wake-up call that elections have consequences,” Ms. Rice said in an interview. “But for people on Long Island, they don’t want to just hear about that. They want to hear about how we’re going to get inflation under control and public safety,” she said, adding both were politically thorny issues for Democrats in New York.Republicans are looking to replicate their success from 2021, when the party used visceral ads of assaults and break-ins to help capture a slew of races across Long Island. They ousted Laura Curran, the Democratic Nassau County executive, in November, and won control of the Nassau district attorney’s office despite running a first-time candidate against a well-known Democratic state senator.Democratic operatives are quick to caution that 2021 was an off-year election, when Republicans typically are more successful in getting voters to the polls. Indeed, there are more Democrats than Republicans registered to vote in the district, and political analysts have forecast it as more favorable for Democrats.Still, almost a quarter of voters are unaffiliated with either party. Some high-ranking Democrats have privately raised concerns that the contest is being overlooked by the Democratic Congressional Campaign Committee, which did not include it in its national “Red to Blue” slate of competitive races, a designation that provides field work and helps attract financial support from national donors.Interviews this month with more than a dozen voters in Nassau County showed that public safety, inflation and immigration remained animating issues among Republicans and swing voters who typically play an outsize role in elections here..css-1v2n82w{max-width:600px;width:calc(100% – 40px);margin-top:20px;margin-bottom:25px;height:auto;margin-left:auto;margin-right:auto;font-family:nyt-franklin;color:var(–color-content-secondary,#363636);}@media only screen and (max-width:480px){.css-1v2n82w{margin-left:20px;margin-right:20px;}}@media only screen and (min-width:1024px){.css-1v2n82w{width:600px;}}.css-161d8zr{width:40px;margin-bottom:18px;text-align:left;margin-left:0;color:var(–color-content-primary,#121212);border:1px solid var(–color-content-primary,#121212);}@media only screen and (max-width:480px){.css-161d8zr{width:30px;margin-bottom:15px;}}.css-tjtq43{line-height:25px;}@media only screen and (max-width:480px){.css-tjtq43{line-height:24px;}}.css-x1k33h{font-family:nyt-cheltenham;font-size:19px;font-weight:700;line-height:25px;}.css-ok2gjs{font-size:17px;font-weight:300;line-height:25px;}.css-ok2gjs a{font-weight:500;color:var(–color-content-secondary,#363636);}.css-1c013uz{margin-top:18px;margin-bottom:22px;}@media only screen and (max-width:480px){.css-1c013uz{font-size:14px;margin-top:15px;margin-bottom:20px;}}.css-1c013uz a{color:var(–color-signal-editorial,#326891);-webkit-text-decoration:underline;text-decoration:underline;font-weight:500;font-size:16px;}@media only screen and (max-width:480px){.css-1c013uz a{font-size:13px;}}.css-1c013uz a:hover{-webkit-text-decoration:none;text-decoration:none;}How Times reporters cover politics. We rely on our journalists to be independent observers. So while Times staff members may vote, they are not allowed to endorse or campaign for candidates or political causes. This includes participating in marches or rallies in support of a movement or giving money to, or raising money for, any political candidate or election cause.Learn more about our process.Joe O’Connor, a 75-year-old Vietnam veteran from Freeport on Long Island’s South Shore, is not registered with either party. He voted against Mr. Trump in 2020 but said he was still unsure how he would vote in November, noting that chief among his concerns were education, homelessness and safety in New York City.“New York has come back great, and I’m really happy with that,” said Mr. O’Connor, a former teacher who frequently visits museums and Broadway shows in the city. “But it’s got to be cleaned up, and it’s got to be safe for people.”Democrats, for their part, have homed in on abortion rights and the threat to democracy as central campaign themes, hopeful that the recent legal setbacks that have thrust former President Donald J. Trump back into the news will also boost their chances in a state where Mr. Trump remains deeply unpopular.Delis Ortiz, 20, who said she would vote for her first time in November, said that while her top concern was keeping up with rising grocery prices, she would most likely vote Democratic in part because of the party’s stance on abortion rights.“I believe that every person has a right to their own body,” said Ms. Ortiz, a barista at an upscale coffee shop in Garden City. “Nobody should have that power over anyone else, ever.”Those themes are playing out visibly in the competitive race to replace Representative Thomas R. Suozzi, a centrist Democrat who has represented the Third District, in northern parts of Nassau County and parts of eastern Queens, since 2017 but decided not to run for re-election to pursue an unsuccessful run for governor this year.Robert Zimmerman, a small-business owner and well-known Democratic activist, has repeatedly sought to cast his Republican opponent, George Santos, as too extreme to represent the district, highlighting Mr. Santos’s apparent support of abortion bans and his attendance at the pro-Trump rally in Washington on Jan. 6.Robert Zimmerman, a Democrat, is facing George Santos, a Republican, in a contest to fill an open seat vacated by Representative Thomas Suozzi.Johnny Milano for The New York Times“Long Island can very well determine who has the majority in Congress,” Mr. Zimmerman said over coffee at a diner in Great Neck this month. “And frankly, George Santos represents the greatest threat to our democracy of any candidate running for Congress in New York State. I really can’t underscore that enough.”In a statement, Charley Lovett, Mr. Santos’s campaign manager, accused Mr. Zimmerman of trying to “distract voters from the disasters that Joe Biden and Nancy Pelosi’s policies have caused with Robert Zimmerman’s full support.”Their matchup also has history-making potential: The race appears to be the first time that two openly gay candidates for Congress have faced off in a general election.The governor’s election could also play a role in some House races on Long Island, which has emerged as a key battleground in the race between Gov. Kathy Hochul, a Democrat, and her Republican opponent, Representative Lee Zeldin, who has represented most of Suffolk County in Congress since 2015.Ms. Hochul has held a significant lead in most public polls, and she held a narrow five-point lead in the New York City suburbs in a Siena College poll released on Wednesday. Even so, Republicans are hoping Mr. Zeldin’s support on Long Island could help drive its voters to the polls, buoying the party’s House candidates, though Democrats are betting that their barrage of attack ads portraying Mr. Zeldin as a right-wing extremist will help the party animate Democrats and swing more moderate voters in their favor.Mr. Zeldin’s entry into the governor’s race paved the way for Democrats to try and flip his now-open congressional seat in the First District on the eastern end of the island, one of the few Republican-held seats in the country that is open and considered competitive. But Democrats face an uphill battle: The seat is projected to slightly favor Republicans, who have held the district since Mr. Zeldin wrestled it from Democratic control in 2014.The Democrat in the race, Bridget Fleming, a former assistant district attorney and current county legislator, has nonetheless outpaced her opponent in fund-raising and recently received the endorsement from the union that represents police officers in Suffolk County. She was also added to the Democrats’ Red to Blue program in June.A moderate, she has centered her campaign in the district, a mix of working-class and wealthy residents, on affordability and conserving the environment — a top issue for fishermen and farmers, as well as the tourism industry, on the island’s East End — but also on protecting women’s right to choose.“There’s no question that fundamental freedoms are under assault in our country,” said Ms. Fleming. “The exploitation of the extremes that we’ve seen recently is electrifying people who are standing up to fight for themselves.”In an interview, her opponent, Nicholas LaLota, brushed off Democrats’ almost singular focus on reproductive rights, saying that New York already had some of the strictest protections in the country.“Here in New York, nobody’s abortion rights are under attack or assault,” said Mr. LaLota, a former Navy lieutenant who works in the Suffolk County Legislature. “So those folks who want to campaign on abortion, they should run for state office, not federal office.”He added that voters in the district “who live paycheck to paycheck were more concerned about rising interests rates and prices.”Democrats are facing an even steeper climb to unseat Representative Andrew Garbarino, a well-funded Republican who represents the Second District on the South Shore that is among the most affluent in the country. Opposing Mr. Garbarino is Jackie Gordon, an Army veteran, who lost to Mr. Garbarino in 2020. More