Muriel Bowser at a candidates forum. (Michael S. Williamson/Washington Post)

With multiple candidates jostling for the title of “top challenger” to District Mayor Vince Gray in the April 1 Democratic primary, D.C. Council member Muriel Bowser has emerged as the one to beat.

Bowser, once a protégé of former mayor Adrian Fenty, represents Ward 4 in the city’s northern corner. She has apparently gained a small but meaningful advantage through a mix of strong organization, substantial campaign funds and the promise of appealing to all parts of the District.

Bowser could fade, of course. There’s no broad groundswell of excitement around her campaign — or anybody else’s.

Other major candidates, such as fellow council members Jack Evans (Ward 2) and Tommy Wells (Ward 6), say they also have good prospects to unite anti-Gray voters and win the nomination.

But it’s telling that both Evans and Wells describe Bowser as their strongest opponent, other than Gray. So does the campaign of another candidate, businessman Andy Shallal.

“Muriel — she would be the only other one,” Evans told me last week.

“I don’t see Evans. I don’t see Shallal,” Wells said.

Bowser is “definitely” ahead of Evans and Wells, said Shallal’s communications director, Dwight Kirk.

This year’s unusual political climate in the District makes it especially valuable to be identified as the most credible alternative to Gray. Polls show many voters are looking for somebody new, mainly because of the scandal over dirty tricks and illicit funds in Gray’s 2010 campaign.

That means there’s a good chance of seeing a “snowball effect” benefiting whichever challenger seems to have the best shot at winning.

No big issue has emerged to dominate the campaign. In the first round of candidate forums, of which I’ve attended three, all of the candidates urged better schools, more affordable housing, jobs, public safety, etc.

They differed in emphasis, but I haven’t heard anything yet that might arouse a surge of enthusiasm. That suggests organization, money and breadth of appeal will be decisive.

With just over five weeks to go before early voting begins on March 17, Bowser seems to have an edge overall in those areas.

In a sign of good organization, Bowser has won both of the straw polls conducted so far in individual wards.

She has been second only to Evans in raising funds. Gray, who started late, is in third place. The other five candidates are well behind.

Finally, Bowser is pursuing Fenty’s successful 2006 strategy of positioning herself as a candidate who can bridge the city’s racial divide. She’s an African American who has successfully won support from white precincts.

Her two principal competitors for the anti-Gray vote — Evans and Wells — are white. Perhaps 2014 will see the District elect a white mayor, but it hasn’t happened before.

“Our campaign is the only one that has a path to overtake Vince Gray,” Bowser said. “We have a lot of energy behind our campaign in all eight wards. We’re the only campaign, including the incumbent, that can say that.”

The principal rap on Bowser is a thin legislative record in her seven years on the council. Evans is particularly forceful in contrasting his 23 years in office with the records of Bowser and Wells.

“Muriel, Tommy — they haven’t done anything. They’re just running their mouths,” Evans said.

But Evans is hampered on the stump by his reluctance to publicly criticize Gray. His pitch boils down to: If you already dislike Gray, then vote for me, because I’m the only other person with enough experience to run the city.

Wells is emphasizing ethics and highlighting his refusal to accept corporate donations.

He has a strong base among white voters in his home ward on Capitol Hill but acknowledges that he needs to do more to attract blacks. With that in mind, he’s begun emphasizing that he began his career as a social worker.

“Many people in the city are still getting to know me,” Wells said.

Of the remaining candidates, I think only Shallal has the potential to break out of the pack. He’s a crowd-pleasing speaker who forcefully decries the gap between rich and poor in the city.

But Shallal began the campaign with little name recognition and has no experience in elective office.

There’s no guarantee that any of Gray’s opponents will rise above the others and effectively make the primary a one-on-one contest. If anybody is going to give him that fight, however, Bowser currently seems like the safest bet.

I’m taking a short break. Column resumes Feb. 16. For previous columns, go to mccartney.