(CNN) -- The eyes of the political world are on Atlanta's northern suburbs Tuesday as voters go to the polls in a special election that's about much more than the House seat up for grabs.
Democrat Jon Ossoff is aiming to win the seat outright -- topping 50% and avoiding a runoff. If he succeeds, it would deliver a major blow to President Donald Trump and suggest the GOP's House majority is in jeopardy in the 2018 midterms.
The race is to replace new Health and Human Services Secretary Tom Price in Georgia's 6th District -- long a reliable Republican stronghold and the seat Newt Gingrich held on his rise to becoming House speaker in the 1990s.
It's a "jungle primary" featuring 18 candidates -- including 11 Republicans and four Democrats. If no one tops 50%, the top two finishers will advance to a June runoff.
Really, though, it's all about Ossoff -- the only candidate who is expected to be in the ballpark of 50%.
The 30-year-old former congressional staffer and documentary filmmaker carries the weight of the anti-Trump resistance on his shoulders. In large part thanks to the liberal blog Daily Kos, Ossoff raised a staggering $8.3 million in the first quarter of 2017 -- a figure made possible by his stature as the only Democrat with a clear path to flipping a Republican-held seat in one of the four special elections to replace Trump Cabinet selections this spring.
Ossoff benefits from being the only serious Democrat candidate, while Republicans have seen infighting among their 11 candidates -- including several with high-profile support and campaigns, including former Georgia Secretary of State Karen Handel, state Sen. Judson Hill, businessman and former state Sen. Dan Moody and Johns Creek City Councilman Bob Gray.
For Democrats, the race also offers a preview of its 2018 roadmap. The suburban district has all the characteristics -- diversity, including Latino voters, higher-than-average education levels and a younger population -- of those it hopes to flip in areas like Orange County, California, and the Texas suburbs.
It took a sudden evolution for the district to become competitive at all. Mitt Romney carried it over Barack Obama in the 2012 presidential election by more than 23 percentage points, after all.
But 2016 told a much different story. Trump bested Hillary Clinton in the district by just 1.5 points. And Clinton carried Cobb County -- a key population base of the district. It was the first time a Democrat had won Cobb County since Georgia's Jimmy Carter was on the ballot.
Trump has repeatedly weighed in on the race in recent days, tweeting Monday: "The super Liberal Democrat in the Georgia (congressional) race tomorrow wants to protect criminals, allow illegal immigration and raise taxes!"
He also recorded a robocall attacking Ossoff the evening before the special election and telling voters they need to vote for any of the Republicans in the field.
"If you don't vote tomorrow, Ossoff will raise your taxes, destroy your health care and flood our country with illegal immigrants," Trump said. "Vote Republican."
Republicans have long believed that all they must do is survive Tuesday without Ossoff hitting the 50% mark. If he falls short, the party believes Republican voters will coalesce around their nominee, preventing Ossoff's numbers from climbing any higher in a runoff.
Democrats, though, note that Ossoff -- who has dominated the airwaves -- has still faced an onslaught of more than $4 million in attack ads from the National Republican Congressional Committee and the Congressional Leadership Fund super PAC.
"Ossoff will finally have an opponent to set up a clear and beneficial contrast. Until now, the Republican candidates have faced very little scrutiny or negative ads," said Meredith Kelly, the Democratic Congressional Campaign Committee's communications director.
Ossoff has faced criticism for the amount of money coming from outside the region and the fact that while he's originally from the district, he doesn't currently live there now.
Ossoff defended himself against the criticism Tuesday.
"I grew up in this district," Ossoff said, speaking to CNN's Alisyn Camerota on "New Day." "I grew up in this community. It is my home. My family is still there."
Ossoff has said he'll move back to the district after his girlfriend finishes medical school nearby.
"It's something I've been very transparent about," he said. "I am proud to be supporting her career. As soon as she finishes her medical training, I will be 10 minutes back up the road where I grew up."
Election Day has not been entirely without drama: State officials are investigating the thefts of several voting machines over the weekend, Candice Broce, spokeswoman for Georgia's Secretary of State, told CNN on Tuesday.
The machines were stolen Saturday from a voter poll manager's vehicle, according to a statement from the Cobb County elections office. The Express Poll Units are used primarily for voter check-in for one precinct.
"It is unacceptable that the Cobb County Elections Office waited two days to notify my office of this theft," Georgia Secretary of State Brian Kemp said in a statement. "We have opened an investigation, and we are taking steps to ensure that it has no effect on the election. I am confident that the results will not be compromised."
Broce says their office has re-configured the coding for Tuesday's election to render the stolen units ineffective and are working with local law enforcement to track down the perpetrators and investigate any suspicious activity at polling places.