• Democrat Tom Suozzi has won the New York special election to replace expelled former Rep. George Santos, NBC News projects.
• Suozzi is projected to defeat Republican Mazi Pilip.
• The outcome flips a red seat blue and further narrows Republicans' slim House majority.
• Santos was ousted from Congress under a cloud of scandals and criminal charges.

Democrat Tom Suozzi has won the New York special election to replace expelled former Rep. George Santos, NBC News projects, flipping a red seat blue and further narrowing Republicans' slim House majority.

The seat representing New York's 3rd Congressional District had been vacant since Santos was ousted from Congress late last year under a cloud of scandals and criminal charges.

Suozzi, who previously represented the district, is projected to defeat Republican Mazi Pilip.

Surveys conducted before Election Day showed a tight race between Suozzi and Pilip in the district, which covers parts of Long Island and Queens. But NBC and other outlets projected the outcome of the race less than 90 minutes after polls closed.

"Let's send a message to our friends running the Congress these days: Stop running around for Trump, and start running the country," Suozzi said in a victory speech.

As Suozzi took the stage, a pro-Palestinian protester confronted him and screamed, "You support genocide!" The protester was swiftly taken of the stage.

The special election, conducted in spite of a major snowstorm that barreled through the northeast Tuesday morning, could have a major impact on the balance of power in Congress.

Suozzi could be sworn into Congress within days, raising the number of House Democrats to 213 — a relative hair's breadth from the chamber's 219-member GOP majority. That means that if the full House is voting, Republicans can only allow two defectors to break ranks and still pass legislation along party lines.

Both parties poured millions of dollars into the contest, but Democrats have spent twice as much as Republicans on advertising — $13 million in total over just 10 weeks, according to The New York Times.

Pilip, a Nassau County legislator, tried to make the race a referendum on immigration, a galvanizing issue for Republicans across the country, and one that has rankled New York leaders in recent months.

But Suozzi took a harder line on immigration than many of his fellow Democrats running for Congress, and he countered Pilip's attacks by blasting her as an extremist for opposing a bipartisan border deal.

Democrats throughout the race sought to tie Pilip to Santos, who had been shunned by his own constituents long before he was booted from his seat.

Some observers have been tempted to view Tuesday's matchup as a bellwether for the November general election, believing a concrete result in a competitive race offers more clarity about the political landscape than a series of ever-changing polls.

But special election turnout shares little DNA with the general electorate, according to a New York Times analysis earlier this month. Special election voters tend to be more engaged, and more partisan, than those in general elections, the Times found.

That hasn't stopped Republicans and Democrats alike from holding up Suozzi's win as a warning sign for the coming election, including the likely rematch of President Joe Biden and former President Donald Trump.

"Let's just say the quiet part out loud. Donald Trump continues to be a huge weight against Republican candidates," said the presidential campaign of former United Nations ambassador Nikki Haley, Trump's last GOP primary challenger.

Biden's reelection campaign, meanwhile, declared, "Donald Trump lost again tonight. When Republicans run on Trump's extreme agenda – even in a Republican-held seat – voters reject them."

Suozzi won't have too long to celebrate his victory: He will have to run again in November to be elected to a full two-year term. Both Suozzi and Pilip have already committed to campaigning in the general, no matter who wins on Tuesday.

In addition to fighting each other, Suozzi and Pilip had to contend with another challenge: a major storm that began overnight and has already dumped multiple inches of snow on New York City.

NBC News reported low turnout at several polling locations in the morning, including some identified as "popular" sites by the Nassau County Clerk's Office. Just 199 voters cast ballots at the Syosset site between 6 a.m. and 11:25 a.m., for instance, and volunteers there blamed the storm for the lower-than-expected numbers.

Last year, a federal grand jury in Long Island charged Santos with an array of crimes, including spending campaign contributions on personal luxury goods and lying on his House financial disclosure forms.

He pleaded not guilty to those charges and another raft of allegations that was added to his case five months later.

Santos had served just 11 months in Congress by the time he was expelled. His criminal trial is set for mid-September.

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