WOODBURY, N.Y. — A decisive victory Tuesday for Tom Suozzi flipped a bellwether New York House district into the Democratic column, thinning an already small House GOP majority and potentially offering a preview of the campaign tactics in 2024 battleground races nationally.

Suozzi, a former Democratic congressman, defeated Republican Mazi Pilip in the special election to replace former GOP Rep. George Santos in the Long Island-based 3rd District.

Santos was expelled from Congress in December following his indictment on federal charges and a damning Ethics Committee report. He has pleaded not guilty and is set to go to trial in September.

While special elections always have unique dynamics, including lower turnout, there are some key takeaways from Tuesday’s election with national implications. That includes what the results mean for the rest of the year in Congress and how aspects of this campaign could show up in other races. 

Here’s what we learned:

Migration and border concerns weren’t everything for GOP

Republicans went all-in on the issue of immigration as their ticket to victory — and fell short. Ads from Pilip and GOP outside groups hammered Suozzi as a tool of the left-wing “Squad” that opposes immigration enforcement. A recent Newsday/Siena College poll showed that it was Pilip’s strongest issue in the race. But it wasn’t enough to claim victory, and Democrats took note of exactly how Suozzi fought on the issue.

Suozzi countered it by endorsing the bipartisan deal to toughen border and asylum laws and depicting Pilip, who rejected the bill, as beholden to former President Donald Trump and a far-right GOP.

“Despite all the lies about Tom Suozzi and the Squad, about Tom Suozzi being the godfather of the migrant crisis, about ‘Sanctuary Suozzi,’ despite the dirty tricks, despite the vaunted Nassau County Republican machine, we won,” Suozzi said in his victory speech. “It’s time to start working together. So our message is very clear. Either get on board or get out of the way.”

Some Democrats said in the days leading up to the race that Suozzi’s decision to directly rebut Republican immigration attacks, acknowledging the influx of migrants and going on offense, could be an effective strategy for Democrats moving forward.

Suozzi also signaled that his willingness to address thorny issues like immigration and the economy helped fuel his victory. 

“This race was centered on immigration and the economy, much like the issues all across the country,” Suozzi said. “We won this race — we, you won this race — because we addressed the issues and we found a way to bind our divisions.” 

House majority gets even thinner

Republicans already have a paper-thin House majority. What’s thinner than paper? Speaker Mike Johnson, R-La., is about to find out. He’s already struggling to govern with the margin he has now, which is about to shrink from a 219-212 edge to 219-213, further empowering the Democratic minority.

“Let’s take our country back from the dividers,” Suozzi said Tuesday night in his victory.

It’s no coincidence that Republicans voted to impeach DHS Secretary Alejandro Mayorkas by a mere one-vote margin just a few hours before polls closed in New York. Had Suozzi been in Congress for the vote, it would have failed.

That illustrates the magnitude of a single vote in the current House of Representatives, which is eyeing deadlines on major issues like avoiding a government shutdown next month, reauthorizing the Federal Aviation Administration, deciding what to do about warrantless surveillance powers and a farm bill.

After the result, Suozzi told NBC News here that he wants to be sworn in this week. “I hope so,” he said.

A source with knowledge of his intentions said it could be as early as Thursday.

Blue-to-red districts are still in flux

This was one of the small group of suburban battleground districts that flipped from blue to red in 2022 and gave Republicans control of the House. Now it has flipped back. The result indicates that this district — and potentially others with a similar mix of red and blue — are still in flux and not necessarily ready to stick with the GOP.

Many of the same districts will be back in play in the 2024 race for the House majority, giving Democrats a boost of confidence heading into the fall. Surveys show Biden to be unpopular nationally and in battleground territory, but a host of recent off-year and special elections don’t indicate that it’s translating at the ballot box, a theme the Biden campaign has pointed out.

Will presidential election-level turnout give Republicans the boost they’ve been looking for? NBC News’ polling over the past year has shown Biden doing better among more engaged voters who showed up in both the 2020 and 2022 elections, but more poorly among the remainder of voters.

After this result in another relatively low-turnout contest, compared to what we can expect in the fall, the GOP will be hoping that its fortunes change when turnout rises.

GOP still struggling on abortion

Pilip’s loss on Tuesday underscores how Republicans are still struggling to navigate abortion which has helped Democrats notch wins in a variety of contests in the year and a half since the Supreme Court overturned Roe v. Wade.

Democratic outside groups, including House Majority PAC, targeted Pilip on abortion in TV ads, featuring footage of the Republican describing herself as “pro-life.” Pilip contended that she would not support a federal abortion ban if elected, even calling the decision to have an abortion a personal choice.

In a heated exchange in their one and only televised debate last week, Pilip dodged questions from Suozzi on whether she would describe herself as “pro-choice.” And she would not say if she would vote to protect abortion access at the federal level, reflecting broader difficulties for the GOP on the issue in swing districts.

Special elections are still special

Democrats were quick to cheer Suozzi’s victory as a sign that voters are rejecting Trump’s agenda. And while this special election does have some lessons for both parties, it’s worth remembering this election was, well, special. 

It was unique from the start, thanks to the shadow Santos cast over the race. Democrats attempted to tie Pilip to Santos, arguing that the lesser-known legislator would be a risky bet for voters. The Santos debacle was still fresh on voters’ minds ahead of Tuesday’s election, with some saying they were embarrassed by the scandal.

County party leaders were also able to handpick their nominees due to the state’s special election rules. Democrats quickly coalesced around Suozzi, who was well-known among voters as the district’s former congressman. Republicans landed on Pilip, hoping to leverage her unique biography as a Jewish, Ethiopian immigrant who served in the Israel Defense Forces.

The race also played out over a matter of weeks, while future races in the 3rd District and other House battlegrounds will be fought over several months. 

Special election turnout is also unique — and not just because voters aren’t used to casting ballots in February. A winter storm also walloped the New York City area on Tuesday, which may have kept some voters home.