Democrat Brian Nathan is leading his Republican opponent by a razor-thin margin in the Tampa-area special state Senate election to replace Jay Collins.

With all precincts reporting, Nathan, a union leader and Navy veteran, led former state Rep. Josie Tomkow by half a percentage point, 50.25% to 49.75%. That margin, if it holds, would trigger a machine recount.

That means it could take days to know the final outcome of the race.

But Nathan was celebrating the results Tuesday evening, and said that Tomkow had called him to concede. The Times could not reach Tomkow for comment Tuesday night.

A victory by Nathan would represent a major upset in a district that Collins, a Republican, won by almost 10 points in 2022. Republicans hold an advantage of about 22,000 voters in the district.

More Republicans turned out than Democrats at the polls. The difference likely came down to third-party voters — more than 13,000 had cast their ballots as of 6 p.m. Tuesday.

“It came down to turnout,” Nathan said. “I really think this came through because we were speaking to (third-party voters) where they were at.”

Nathan’s performance is in keeping with a nationwide trend. In 20 state legislative races across the country, Democrats have improved upon former Vice President Kamala Harris’ performance by 10.5 points on average, according to reporting from Axios.

The Associated Press had not called the race for Nathan as of 10 p.m. But the Democratic Legislative Campaign Committee, which funds state legislative races across the country, declared victory for Nathan and another Florida Democrat, Emily Gregory, who flipped a Palm Beach County state House seat that went for President Donald Trump by about 10 points.

“Mar-a-Lago and Tampa just flipped red to blue, which should have Republicans sweating the midterms,” Democratic Legislative Campaign Committee President Heather Williams said in a statement. “State Democrats have now flipped a staggering 30 districts red to blue since Trump’s election.”

David Jolly, a Democratic candidate for governor, also celebrated Nathan and Gregory as winners.

“Tonight, (voters have) rightfully put their trust in Sen. Elect Brian Nathan and Rep. Elect Emily Gregory,” Jolly said in a statement. In November, we have the historic opportunity to elect a Democratic Governor. It’s clear. Change is here.”

Senate District 14 covers much of Hillsborough County west of Interstate 275, including South and West Tampa, as well as suburbs like Town ‘N Country, Westchase, Carrollwood and Lutz.

More than a quarter of eligible voters cast their ballots in Tuesday’s special election. That’s an improvement compared to the last time Hillsborough County held a special legislative election in 2017. Turnout in the election for House District 58, which at the time covered parts of east Hillsborough, was just over 15%.

There are still 186 provisional ballots and other ballots awaiting review, said Gerri Kramer, spokesperson for the Hillsborough Supervisor of Elections office. Some may be rejected, she said.

Voters have until Thursday to correct those ballots. If the race is still within recount territory (a margin of 0.5 percentage points or less), that process would begin March 31, Kramer said. Elections officers will decide Friday whether a recount is needed.

Some who voted said they knew little about the candidates. About a dozen voters who spoke with the Tampa Bay Times Tuesday said they cast a ballot either to support their party or because such civic engagement was the right thing to do.

Tomkow had two major advantages: a Republican registration advantage in the district and a sizable fundraising lead.

Tomkow outspent Nathan more than 3-to-1. She also received more than $400,000 in in-kind contributions from the Florida Republican Senatorial Campaign Committee.

But Nathan said he sees parallels between himself and Texas Democrat Taylor Rehmet, an Air Force veteran and machinists union leader who won a special election in a solid red state Senate district that Trump carried by 17 points. Rehmet was also vastly outspent by his Republican opponent.

The results Tuesday suggest Florida is not immune to surprise Democratic victories, Nathan said.

“I think (my victory) says Florida is more in play than the prognosticators have said up until now,” he said. “That’s not to say it’s going to be a walk in the park to flip the state. But I think we can flip large parts of the state.”

Nathan, should he win, will be on the ballot again in November. But for now, he said he’s ready to fight to preserve Florida’s congressional map in a special session next month.

And Florida lawmakers still have to nail down the state budget.