With less than seven weeks to go before the primary election in the Baltimore mayor's race, leading Democratic candidates say they're planning a big increase in campaign spending — especially on television advertising.

Both state Sen. Catherine E. Pugh and former Mayor Sheila Dixon immediately launched new fundraising appeals after a Baltimore Sun-University of Baltimore poll this week showed them in a virtual tie for the lead in the race. Businessman David L. Warnock was in third place.

Pugh said Friday that the poll shows she “absolutely” is the candidate who is surging in the race — and that supporters are quickly joining her ranks.

“We certainly have momentum. It looks good for us,” she said. “But I'm still working like I'm 10 points behind.”

But Dixon, who has been the front-runner for months, pointed to the poll's finding that she has the most loyal following — voters she's confident will turn out on Election Day, April 26. She noted that she has yet to run a television ad, while Pugh and Warnock have spent thousands on such advertising.

“Cathy's been on TV. Warnock's been on TV. They've spent all these dollars on TV,” Dixon said. “I don't think the poll is reflective of what we're seeing as we knock on doors and talk to people in the communities. Nobody has the strategy and plan that we have.”

Dixon said she plans to launch TV ads soon, and increase her use of a radio ad in which Bishop John Bryant, former pastor of Bethel AME Church, endorses her. “In this season of her life, she is the one who can take the city to a higher place,” he says in the ad. “The Sheila Dixon I know is a woman of wonderful values.”

Like Pugh, Warnock also pointed to the poll's results as a sign of momentum for his campaign. He has spent more than $650,000 in television ads — some of which feature him driving around the city in his old pickup truck — and has no plans to slow down.

“Look at how far we've come,” he said. “At Thanksgiving, nobody knew who I was. We wanted to go up on TV early and introduce myself,” he said. “The truck has resonated in ways that I never would have imagined. ... It's a three-person race right now.”

Matthew Crenson, emeritus professor of political science at the Johns Hopkins University, said he believes the purchase of television advertising has made a tremendous difference in the race, specifically for Pugh, who released her third commercial Thursday.

The latest ad features a victim of domestic violence whom Pugh mentored and helped embark on a successful career by attending college with a senatorial scholarship.

“It is surprising that Catherine Pugh has essentially caught up,” Crenson said. “It shows advertising advances candidacy.”

The poll showed Pugh and Dixon in a virtual tie for first place, with 26 percent and 24 percent, respectively.

Warnock had 10 percent, followed by City Councilman Nick J. Mosby with 6 percent, lawyer Elizabeth Embry with 5 percent and City Councilman Carl Stokes with 3 percent.

The survey of 407 likely Baltimore Democratic primary voters was conducted March 4 to 7 and has a margin of error of 4.9 percentage points.

The poll also showed that 25 percent of likely Democratic primary voters are undecided. And nearly half of those who favor a candidate are open to changing to someone else.

The winner of the Democratic primary for years has gone on to become mayor of Baltimore, where Democrats outnumber Republicans by nearly 10-1.

“People really haven't started paying attention yet,” Crenson said.

“One of the biggest numbers in the poll was the undecided. That could transform the rank ordering completely, given that we're more than a month away from the primary.”

Steve Raabe, president of OpinionWorks, the Annapolis-based firm that conducted the poll, said there are currently “two viable candidates” in the race, with several others who are within “striking distance.”

“Dixon has not significantly moved, while others have,” he said. “It's not that she can't increase her vote, but this has the feeling that there may be a ceiling for her.”

Mosby, in fourth place, said he isn't deterred. He said he plans to begin airing TV ads “when it's the right time.”

“I don't have a million dollars to write a check to go up on TV,” he said, referring to Warnock's use of his own money to finance his campaign.

“But we will get there,” he said.

In recent weeks, Mosby's wife, Baltimore State's Attorney Marilyn J. Mosby, has taken a more visible role in the campaign. She's recorded robo-calls on his behalf and begun sending out fundraising emails for his campaign.

Nick Mosby said he was encouraged by the large number of undecided voters in the poll.

“You have half of the city completely undecided or really aren't strongly connected to one of the top candidates,” he said. “We've been in tough races before. We know how to turn out votes.”

Embry has spent more than $90,000 on television advertising and said she plans to keep spending.

“It's still an open field in terms of the top candidates,” she said. “There are so many undecided voters, and many of Pugh and Warnock voters are willing to choose someone else.

“A lot of people aren't going to focus until the end.”

Stokes began airing his first TV ad Friday. It opens with Stokes holding a gun and argues that city government needs to spend less on policing and more on education.

In it, Stokes invokes his second-place finish to Martin O'Malley in the 1999 mayor's race. “I said this 20 years ago,” Stokes says of arguing for less policing and more education. “Maybe today, people will listen.”

DeRay Mckesson, the prominent Black Lives Matter activist, recently returned from a fundraising trip to New York. He hopes to raise enough by leveraging his large social media following to launch an advertising campaign in the race's homestretch.

As important as TV has been in the race, political analyst Charles D. Ellison emphasized that winning is likely to come down to who has the best door-knocking and get-out-the-vote efforts.

He said such efforts could prove effective for candidates who appeal to younger voters, such as Mosby and Mckesson.

“They've got to find a creative way to bust out the youth vote to offset the dominance of older and senior voters,” Ellison said. “They need to hit those streets very aggressively. They should be out in the streets for the next six weeks — 24 hours a day, 7 days a week — trying to shake every hand in Baltimore.”

Despite Pugh's and Dixon's lead, Ellison said he sees Warnock as a “dark horse” in the race.

“I would not be surprised if we had a situation where, because there are so many black candidates, the black vote is split up so much that Warnock rises to the top,” he said. “I wouldn't dismiss him.”

Roger E. Hartley, dean of the University of Baltimore's College of Public Affairs, said the poll results give candidates more information about how the leaders are winning over voters. That's valuable information to underdog candidates looking to make a run.

Voters who see crime as the city's most important issue were most likely to back Dixon, while those who cited ethics as the most important quality in a mayor tilted to Pugh. Warnock polled best among those who believe jobs and economic growth are the most important issues for a mayor to address.

“This shows a crowded field with so many important issues for voters,” Hartley said.

“If voters are starting to identify a certain candidate with a certain issue, there's an opportunity for rivals to try to make inroads with those voters on that issue.”

Baltimore Sun reporter Yvonne Wenger contributed to this article.

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