In the heart of Long Island, where Republicans have won every major election in the last three years, Tom Suozzi fought through ripping political headwinds to claim victory on Tuesday in a special House election, seizing a coveted swing district that had been held by George Santos.
The outcome flipped one of the five House seats Democrats need to retake the majority in November, giving the party a badly needed shot of optimism. But Mr. Suozzi’s campaign also provided something that may prove more valuable, a playbook for candidates across the country competing on turf where President Biden and his party remain deeply unpopular.
The strategy went something like this: Challenge Republicans on issues that they usually monopolize, like crime, taxes and, above all, immigration. Flash an independent streak. And fire up the Democratic base with attacks — in this case, nearly $10 million in ads — on the abortion issue and former President Donald J. Trump, the likely Republican nominee for the White House.
“It’s a very interesting lesson to Democrats that you can escape your opponent’s attacks on immigration by not only leaning into the issue, but doubling down on it,” said Steve Israel, a former congressman from the district who once led the House Democrats’ campaign arm.
“Instead of trying to pivot around the issue, he charged into it,” Mr. Israel added.
One of the most vivid examples came in the race’s final weeks. Mr. Suozzi was on his way to a meeting one morning and learned that his Republican opponent, Mazi Pilip, was about to hold an event at a Queens migrant shelter blaming him for the nation’s growing border crisis.
The situation had all the makings of a political storm for the party in power — one that other Democrats might have written off as a lost cause. But Mr. Suozzi redirected his car through choked traffic, pulled up just in time to follow Ms. Pilip in front of TV news cameras and threw himself squarely into the fray.
“You want to try to respond to what the people are hungering for,” he explained at the January event. “This is what the people are hungering for.”
Mr. Suozzi’s victory was not the only piece of good news for Democrats on Tuesday night. They also won a special election to maintain control of a state House seat in a key battleground, Bucks County in Pennsylvania.
In both cases, the Biden campaign released statements casting the Democratic victories as defeats of Trumpism — a view echoed in part by a spokeswoman for Nikki Haley, Mr. Trump’s last significant, if long-shot, Republican primary challenger.
“We just lost another winnable Republican House seat because voters overwhelmingly reject Donald Trump,” said the spokeswoman, Olivia Perez-Cubas. “Until Republicans wake up, we will continue to lose.”
Mr. Trump, for his part, distanced himself from Ms. Pilip, a registered Democrat who never fully embraced him as a candidate, deriding her as a “very foolish woman.” In a statement on TruthSocial, he wrote in capital letters, “MAGA, which is most of the Republican Party, stayed home — and it always will, unless it is treated with the respect that it deserves.”
Political strategists of all stripes caution against drawing sweeping conclusions from special elections. The contests can offer a snapshot of political energy at a moment in time, but they are far from predictive.
Certainly not everything about Mr. Suozzi’s victory will be replicable. After three decades in local politics, he had the benefit of a strong personal brand, plus a largely unknown opponent and a Republican predecessor who was universally reviled after his expulsion from the House in December.
And if Mr. Suozzi’s run spared the Democrats a full-on election-year freakout, it also laid bare the extent of the party’s challenges ahead. Mr. Suozzi, a longtime ally of Mr. Biden, distanced himself from the president and the national party at nearly every turn. That will prove far more difficult for candidates on the ballot during a presidential election — and some of Mr. Suozzi’s positions would risk blowback from the Democratic base in other, less moderate districts.
“Joe Biden won this district by eight points, Democrats outspent Republicans two-to-one, and our Democrat opponent spent decades representing these New Yorkers — yet it was still a dogfight,” Representative Richard Hudson of North Carolina, the chair of the House Republican campaign arm, said in a statement. “Republicans still have multiple pathways to grow our majority in November.”
Still, Democratic candidates and operatives in New York and Washington were clearly buoyed by Mr. Suozzi’s ability to defang a potent set of issues that typically hamstring the party.
Immigration was by far the most significant. Illegal border crossings reached an all-time high in December. The arrival of more than 170,000 asylum seekers in New York City, straining budgets and the police force, has brought a sense of chaos close to home.
Republicans pummeled Mr. Suozzi with millions of dollars in attack ads portraying him as a Biden flunky who favored open borders. At one point, the Pilip campaign called him the “godfather of the border crisis.” Private survey data showed that a clip of Mr. Suozzi bragging that he had “kicked I.C.E. out of Nassau County” was particularly damaging.
Republicans had used similar fears about an adjacent issue, crime, to fuel remarkable victories around suburban New York since 2021, especially on Long Island. Their successes there in 2022, at a time when Republicans underperformed across the country, almost single-handedly delivered the party’s margin in the House.
But this time, Mr. Suozzi, who watched fellow Democrats all but concede the issue to Republicans that year, was determined not to repeat the mistake.
So, over the course of the two-month race, he broke with party orthodoxy, calling on Mr. Biden to shut down the southern border and demanding that migrants charged with assaulting police officers in Times Square be deported. But his primary focus was bipartisanship, with the message that “solutions are not sound bites.”
When Ms. Pilip rejected a bipartisan Senate deal to boost deportations and fortify the border, Mr. Suozzi turned the tables, arguing that she was putting base politics above national security.
Public opinion polls in the race’s final days suggested that Ms. Pilip still had an advantage among voters concerned about the border issue, but Mr. Suozzi narrowed the trust gap.
Mr. Biden himself has begun testing a similar approach on the issue, blaming Mr. Trump for tanking the bipartisan deal in the Senate. The message has been echoed by other Democrats who cast Republicans as extreme and uninterested in solutions to urgent issues.
“This was such a stark, clear choice of, do folks want members of Congress who are going to fearmonger, or who are going to fix a whole bunch of issues,” said Representative Pat Ryan, a New York Democrat preparing to defend a nearby Hudson Valley swing seat. “We’ve had a year-plus of chaos, division and dysfunction in the House. And to me this is a clear rejection of that.”
