Sen. Bernie Sanders, former New York City Mayor Michael Bloomberg and former Vice President Joe Biden are leading the Democratic primary field in Virginia two weeks ahead of the critical Super Tuesday contests that could reshape the wide-open fight for the nomination.

Sanders and Bloomberg received 22% in Tuesday's Monmouth University poll, with Biden close behind at 18% – within the survey's margin of error. The rest of the field is far behind, with former South Bend, Indiana, Mayor Pete Buttigieg at 11%, Sen. Amy Klobuchar of Minnesota at 9% and Sen. Elizabeth Warren of Massachusetts at 5%.

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But the margin between the top three shrinks among those who identify as Democrats. Virginia doesn't have party registration, and registered voters can choose to participate in either the Democratic or Republican primaries. Among likely Democratic voters, Sanders takes 22%, Biden rises to 21% and Bloomberg receives 20%.

Still, 11% of likely primary voters are undecided just two weeks out from Virginia's primary, which is one of 14 state primaries or caucuses that'll be held on March 3 and where 34% of pledged delegates will be up for grabs. Virginia has a total of 99 pledged delegates, which will be awarded proportionally. And only 25% of likely Democratic voters are "firmly decided" on their preferred candidate, illustrating the fluid nature of the primary.

"Virginia provides an interesting test on Super Tuesday. A wide range of candidates appeal to voters here and it is very much a jump ball at this point," Patrick Murray, director of the Monmouth University Polling Institute, said.

As the contest starts to move away from the four early states, candidates like Sanders and Biden have taken more direct aim at Bloomberg, who is completely funding his campaign and saturating the media markets with advertising. As a centerpiece of his campaign, Sanders has railed against billionaires and corporations, making the multibillionaire media mogul a prime foil.

In recent weeks, Sanders and Biden – as well as other candidates – have accused Bloomberg of trying to buy the 2020 election. And those tensions are all but certain to flare up at Wednesday's debate in Nevada days ahead of the state's caucuses. Bloomberg qualified and is set to compete in the contest, his first primary debate of the campaign season.

Meanwhile, Bloomberg has largely focused on his own campaign, with biographical advertising emphasizing his time as New York City mayor and his relationship with former President Barack Obama. The former mayor has criticized progressive plans like "Medicare for All" and could decide to draw that contrast with Sanders and Warren at Wednesday's debate. But he will also need to defend his past record, including policies like stop-and-frisk, which has come under intense scrutiny for disproportionately affecting African Americans, though he has apologized since.

Bloomberg has positioned himself as the strongest candidate to defeat President Donald Trump and has trained most of his fire on the president rather than his Democratic opponents. But on Monday, Bloomberg's campaign switched gears with a digital ad criticizing the behavior of Sanders' supporters.

"It's a shameful turn of events to see Bernie Sanders and Donald Trump employ the very same tactics against Mike, but the reason is clear," Bloomberg's campaign manager Kevin Sheekey said in a statement. "At this point, the primary is Bernie's to lose and ours to win."

A national poll released Tuesday from NPR/PBS Newshour/Marist – the poll by which Bloomberg qualified for the Democratic debate – showed the candidate in second place with 19% behind Sanders, who took the top spot with 31%.

The Vermont senator's support grew by 9 percentage points since December, likely reflecting his momentum from a close race in Iowa and a narrow victory a week later in New Hampshire. Biden lost ground since the December poll and took third place with 15%. The former vice president suffered some setbacks with lackluster performances in Iowa and New Hampshire and is banking on a strong finish in South Carolina at the end of the month. Biden has been openly critical of both Sanders and Bloomberg, who have leapfrogged him in more recent polls.

Bloomberg, who has already spent hundreds of millions on advertising across the country, skipped the early contests and has instead focused on Super Tuesday and beyond – an untested strategy but one that has at least given him a boost in polling.