Democratic candidate Jon Ossoff speaks to volunteers and supporters at a campaign office on April 17, 2017 in Atlanta.

Democrat Jon Ossoff no longer talks about making President Donald Trump furious.

But he may be on the verge of doing just that.

Ossoff, a political newcomer who launched his congressional campaign in the Republican-leaning northern suburbs of Atlanta by urging supporters to "make Trump furious," now speaks in the measured tones of a moderate consensus builder and rarely mentions the president by name.

Local economic development and cutting wasteful government spending are Ossoff's talking points in a race against Republican Karen Handel that has shattered records as the most expensive congressional contest in U.S. history. Polls show it is headed for a tight finish in Tuesday's special election.

An Ossoff victory would rattle Republicans already nervous about next year's congressional midterm elections, and offer Democrats a template on how to campaign in suburban swing districts as they try to erase the 24-seat Republican majority in the House of Representatives.

"It would send a very strong message across the country that we can win these kinds of seats," said Representative Dan Kildee, a Michigan Democrat who campaigned with Ossoff in Georgia this week.

Democrats have much riding on the outcome. On the surface, conditions seem ripe for a nationwide Democratic renaissance, with a historically unpopular Republican president entangled in an investigation for possible obstruction of justice and the Republican agenda largely stalled in Congress.

But Democrats lost two special House elections earlier this year in conservative Kansas and Montana districts that Trump won by double digits last November. A failure in a more competitive district in Georgia, which Trump carried by just 1 percentage point, would be a morale killer for a party that has struggled to develop a coherent message beyond "We're not the party of Trump."

Democrats have steadily lost ground in recent years in state and local races. Republicans not only control the White House and both chambers of Congress, but also hold 33 governor's offices, the most in nearly a century.

Infighting between grass-roots progressives and the party's more mainstream wing has plagued Democrats, who have appeared increasingly vulnerable to Republican attacks portraying them as coastal elites out of touch with working-class Americans.

Ossoff's "Make Trump Furious" slogan quickly endeared him to national anti-Trump activists and pushed him well ahead of 17 rivals in polls in April's non-partisan primary in a district represented by Republicans for decades.

It wasn't enough. The 30-year-old former congressional staffer and documentary filmmaker fell just short of a majority, and outright victory, forcing a closely watched run-off against Handel for the House seat vacated by Tom Price, the new secretary of health and human services who was first elected to the House in 2004.