ATLANTA – It’s a race with national implications that has the White House's attention. And Monday is its last day.

Unless there’s a runoff.

A total of 18 candidates are running in the special election to replace Tom Price, set for April 18. Price is now President Donald Trump's secretary of the U.S. Department of Health and Human Services, Polls throughout the metro Atlanta district will be open from 7 am to 7 pm, and 11Alive will be bringing you the results as they happen on Tuesday night.

Follow 11Alive's extensive digital coverage of the race here.

But as the campaign prepares to enter its last full day on Monday, here’s a look at where it stands, along with a few scenarios of what could happen next:

Jon Ossoff has been this race’s biggest story. Here’s a first-time candidate who doesn’t actually live in the district and who has raised millions of out-of-state dollars in an attempt to flip a congressional seat that has been firmly GOP since 1978. To the dismay of the four other Democrats in the race, Ossoff received the early fundraising and staffing support from the Democratic Congressional Campaign Committee and other blue-leaning PACs, and the money hasn’t stopped pouring in.

VERIFY: Is Jon Ossoff's campaign funded from outside of Georgia?

Overall, Ossoff’s campaign has raised a remarkable $8.3 million in just three months, more than Price himself raised in his last three campaigns over six years. Just 6 percent of Ossoff’s donors live in Georgia.

He's also dominated every poll taken in the district.

For a while, all that money and national attention caused some race watchers to wonder if Ossoff could win without a runoff. However, over the campaign’s last two weeks, his polling numbers have leveled off in the mid-40s; no poll has ever shown him higher than 45 percent.

Also, his top Republican opponents, namely Karen Handel, are hitting Ossoff – hard – over his fundraising sources and his support from some of the nation’s top liberal leaders, specifically former U.S. House Speaker Nancy Pelosi. His opponents have also tried to link him unfavorably to Al-Jazeera, an association that Ossoff himself has tried to clarify.

MORE: Handel slams Ossoff's 'Hollywood liberals'

Still, Ossoff’s ground game is arguably the strongest in the race; his base seems to be the most energized; he’s earned the highest national profile; and in public appearances and debates, he’s refused to be baited into defensive postures about his background or his fundraising sources, staying on message and coming across as reasonable and mature despite being a 30-year-old political rookie.

MORE: Ossoff targeted in 6th district congressional debate

Least likely: Ossoff doesn’t finish first or second.

  • What that would mean: a whole lot of very unhappy Democrats. The party is pinning its hopes for a 2018 midterm congressional reversal of fortunes against President Donald Trump. Democrats are desperately hoping for a strong Ossoff showing Tuesday night.

Less likely: Ossoff wins without a runoff.

  • What that would mean: a whole lot of happy Democrats. For a national party in disarray to pick off a since-1978 GOP stronghold, from a field of 18 candidates without a runoff, would amount to a political earthquake.

More likely: Ossoff finishes first but without more than 50 percent, meaning he’s in a runoff with a Republican.

  • What that means: If you thought the race was nasty now, you haven’t seen anything yet. Expect the national GOP – which has pretty much stayed out of the race so far – to put its full fundraising and political support behind whichever Republican makes the runoff on Tuesday.
  • What it also means: Your phone is going to be ringing off the hook with robo-calls until June 20.
  • What it also means: Ossoff and his campaign will be put to the ultimate test: whether his dollars, his national profile and his volunteers remain strong or wither away just as the real campaign begins.

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PHOTOS: 6th district congressional debate