DUNWOODY, Ga. >> An upstart Democrat leads a special election in a conservative Georgia congressional district as he bids for a major upset, but his margin is narrowing.

After today’s evening poll closings, votes were being counted in the metro Atlanta race in which Democrat Jon Ossoff sought to parlay opposition to President Donald Trump into a victory that would rebuke the White House and embolden Democrats ahead of the 2018 midterm elections.

With early voting totals and about a third of precincts counted, Ossoff was above the majority threshold required to win an 18-candidate primary. But tens of thousands of votes have yet to be counted in Georgia’s 6th Congressional District that stretches across the northern suburbs of Atlanta, and Ossoff’s lead had already started to narrow as more precincts reported.

Republicans nationally and in Georgia acknowledged before polls opened that Ossoff would top the field today. An entire slate—Republicans, Democrats and independents — appeared on one primary ballot.

The question was whether Ossoff would command a majority to claim the seat outright. If not, he would face the top Republican vote-getter in a June 20 runoff. The winner will succeed Tom Price, who resigned to become Trump’s health secretary.

Trump took to Twitter urging Republicans to cast ballots late today. He even mocked Ossoff’s choice of residence — outside the district.

“Just learned that Jon Ossoff, who is running for Congress in Georgia, doesn’t even live in the district. Republicans, get out and vote!” the president wrote.

The contest is testing both parties’ strategies for the upcoming national election cycle. Democrats are expected to have a better shot at snagging the typically Republican seat than they did in last week’s closer-than-expected GOP victory in a Kansas special House election.

Trump did not perform as well as other Republicans last November in the Georgia district, an affluent, well-educated swath filled with the kind of voters Democrats need if they hope to reclaim a House majority next year. Republicans currently hold a 238-193 advantage in the chamber.

Ossoff would be a “disaster” in Congress, Trump declared earlier today on social media, a day after he blasted the “super liberal” Democrat as a champion of criminals, higher taxes and unchecked immigration.

Despite Trump’s Twitter barrage, the White House insisted the race isn’t about the president. “I wouldn’t use the word referendum,” said spokeswoman Sarah Huckabee Sanders. “I think he hopes to have a Republican elected.”

An investigative filmmaker, Ossoff raised more than $8.3 million, mostly from donors far from the northern suburbs of Atlanta. That sum dwarfs what any Republican candidate has spent on the contest.

Ossoff has energized liberals and younger voters, while also aiming for disaffected independents and moderate Republicans.

Cedrick Gulley, a 25-year-old Georgia State University student from the Atlanta suburb of Sandy Springs, compared Ossoff to former President Barack Obama and Sen. Cory Booker of New Jersey. Gulley said today they all “make me feel like my generation is being heard.”

He added that Democrats were “a little lazy” in November, but now “there’s an emergence of people fighting.”

Ossoff has pledged to fight Trump when he “embarrasses” the country. But he’s also said he would “work with anybody in Washington who respects your tax dollars.”

That’s a nod to the Republicans and independents he’d need to win — whether today or in a runoff.

That still wasn’t enough for voters like Matt West, a 45-year-old financial planner from Roswell.

“He lives outside the district, he’s a Democrat, and I just don’t believe that he’d stand up to (House Minority Leader) Nancy Pelosi if the district wanted him to,” West said.

West said he voted for Republican Karen Handel, a former Georgia secretary of state who is an establishment favorite and has led the GOP field.

Republican groups ran a blitz of ads trying to tie Ossoff to Pelosi; a political action committee backed by House Speaker Paul Ryan has spent more than $2 million on those and other attacks.

As for residency, Ossoff concedes that he lives just south of the district, in Atlanta, so that his girlfriend is close to her work at Emory University’s medical complex.

Among other top Republicans in the race, technology executive Bob Gray and two former state senators, Dan Moody and Judson Hill, are battling Handel in a fight for the No. 2 spot.

Handel has maintained distance from Trump, rarely discussing him unless asked. Gray has called himself a “willing partner” for the president.

National Republicans say any of the four competitive GOP candidates could defeat Ossoff in a second round. They predict conservative voters would be energized in a Republican vs. Democrat scenario.

“Republican voters are not going to sit by and let this district go to a Democrat,” Handel said at one of her final campaign stops.