WOODBURY, N.Y. — Democratic former Rep. Tom Suozzi is heading back to Congress after he won the special election in New York’s 3rd District to replace former GOP Rep. George Santos, NBC News projects.

Suozzi’s victory Tuesday over Republican Mazi Pilip cuts Republicans’ already razor-thin House majority by one seat, making legislating even more difficult moving forward. And it could provide a guide for Democrats competing in similar competitive districts this fall, especially when it comes to navigating their political vulnerability on immigration and border security.

The Democrat may seek to be sworn into Congress as early as Thursday, according to a source with knowledge of his thinking. If not, he may have to wait until the end of the month after the House takes an extended recess for President’s Day.

At his victory party Tuesday night, Suozzi thanked a long list of supporters and aides and ran through some of the attacks he faced in the hard-fought contest.

“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,” he said to applause.

Suozzi’s speech was initially interrupted by protesters who accused him of supporting “genocide” in Gaza. One of them walked onstage to shout down Suozzi while holding what appeared to be a Palestinian flag, but he was removed.

Suozzi may have been helped by a winter storm that walloped the New York City area Tuesday, as Democrats built up an early advantage in early votes. But his victory also came amid some built-in advantages in name ID and fundraising as the district’s former congressman and as Democrats outspent Republicans on the airwaves.

“He has the values that I have — to get things done but to take into consideration the people who are in need. And he represents the majority of the middle class,” said Jeanne DeChiaro, who voted for Suozzi in Syosset and said her biggest issues were abortion, immigration, the economy and “the ability to be bipartisan.”

Linda Karpe, a Suozzi voter, said the roads on Long Island were “horrible” on her way to the voting booth and “the cars were swerving all around the place.”

“I think my son wants my inheritance, because he told me ‘it would be OK to drive, Mom,’” Karpe joked. “It was really bad.”

Though President Joe Biden won the Long Island-based district by 8 percentage points, according to calculations from Daily Kos Elections, Republicans have made gains in the area since then. In 2022, Santos won this open seat by 8 points, but he was expelled from Congress in December following his indictment on federal charges and a damning Ethics Committee report that alleged he broke multiple federal laws and misused campaign funds. (Santos has pleaded not guilty and is set to go to trial in September.)

The result is a blow to the Nassau County GOP, which has been energized by a string of victories in recent years amid a backlash to Democratic-run New York City and Albany. Before Santos was ousted, Republicans represented every congressional district on Long Island.

It’s also bad news for Republicans in the House who have struggled to pass even partisan bills. Once Suozzi is sworn in, they’ll face even greater pressure to compromise with Democrats and can only lose two votes to advance GOP legislation, assuming all members are present. House Minority Leader Hakeem Jeffries, D-N.Y., celebrated Suozzi’s win and the shrinking GOP majority on X, writing: “One down. Four to go.”

The National Republican Congressional Committee called the race “an uphill battle” from the outset and called Pilip a “fighter with a bright future within the Republican Party.”