Washington (CNN) – The race to become the Democratic nominee for mayor of Washington, D.C. – a contest that was once defined by a crowded, fractured field – has become a head-to-head competition between incumbent Mayor Vince Gray and Muriel Bowser, a D.C. councilmember.
As voters head to the polls on Tuesday, Bowser has become the most likely challenger to unseat Gray, who a majority of voters believe knew of an illegal shadow campaign that helped him win the mayor's office in 2010.
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According to a recent Washington Post poll, 30% of likely primary voters support Bowser, a number two times greater than a Post survey in January. Gray has 27% support, a number that has remained steady since the race started. The three percentage point difference between the candidates is within the margin of error, making the race a statistical dead heat.
A NBC4/Marist poll released last week also found Bowser with a slight lead in the race. According to the poll, 28% of likely Democratic voters support Bowser, while 26% back Gray.
Since prosecutors began looking into Gray's first mayoral race, ethics have remained an issue for the longtime D.C. politician. Earlier this month, federal prosecutors sought to link Gray to campaign finance allegations made by Jeffrey Thompson, a Washington businessman who plead guilty to conspiracy for masterminding a nearly $670,000 illegal "shadow campaign" for Gray in 2010.
During the Thompson hearing, prosecutors publicly claimed Gray was aware of the illegal fundraising and had agreed with Thompson to cover it up. Gray has not been charged with any wrongdoing and has vowed that he did not know of the shadow campaign and did nothing wrong.
"I think if you look at my life," Gray told CNN earlier this month, "my life is one that I am very proud of and this situation is one that, at best, I can describe as an anomaly."
Gray said he doesn't feel that he did anything wrong in the 2010 campaign, has operated "openly and honestly," and has no plans to step down.
Most voters aren't buying it, though.
According to the Post poll, six in 10 likely Democratic primary voters believe Thompson's allegations are true. And 75% of those polled said the investigation into Gray was fair.
Sixty-one percent of Democratic primary voters also said Gray is not "honest and trustworthy," a number that is slightly up from January.
Despite the ethics questions, Gray has led the nation's capital during a time of booming growth and declining crime rates. Washington, D.C. weathered the national economic downturn that crippled other cities and even Gray's mayoral challengers have acknowledged that economic growth in the past four years has boosted the District.
Because of that, among all registered voters, Gray's job approval remains positive. Fifty-three percent of Washingtonians approve of the mayor's job handling, while 39% have a negative view.
A handful of other candidates remain in the race for the Democratic nomination, but none have experienced the jump in support that has propelled Bowser. The Washington Post, for example, endorsed her earlier this month, citing her open mind to new ideas.
Tommy Wells has maintained steady support in the low teens, with 14% of likely primary voters supporting the councilmember. Jack Evans, another member of the D.C. council, was once considered a contender in the race, but the Post's most recent poll found that Evans' support has been cut in half and now only 6% of likely Democratic voters intend to vote for the longtime D.C. politician.
Unlike in years past, where winning the Democratic nomination for mayor meant the winner in November was a foregone conclusion, whoever wins Tuesday's election is likely to face a contentious challenge from independent councilmember David Catania.
Catania launched an independent bid for the office earlier this month, just two days after federal prosecutors said Gray knew about the 2010 shadow campaign. In his announcement, the gay former Republican highlighted "the importance of playing by the rules" and "a strong commitment to fairness."
"We've overcome big obstacles in the past," Catania said in an email to supporters. "And with your support, together, I'm confident that we can meet these challenges."
According to the Post poll, if Gray wins the nomination, his race with Catania will be extremely close. Among all registered voters, both Gray and Catania received 41% support in a hypothetical general election matchup.
If Bowser wins the nomination, however, Catania will have a much more uphill climb to win the mayor's office. According to the poll, Bowser leads Catania by 30 percentage points.