Maryland’s increasingly contentious gubernatorial race got more negative Thursday when the top two Democratic candidates released tit-for-tat attack ads bashing each other. Campaign finance reports filed earlier this week show candidates with money to burn as the primary approaches.

Doug Gansler’s campaign lobbed the first round, targeting front-runner Anthony Brown for his decision to skip a televised debate at Baltimore’s Fox 45 on Tuesday. (The campaigns disagreed over how many debates had been agreed upon.) The ad shows Brown’s empty lectern on the stage between the attorney general and Del. Heather Mizeur. A caption questions whether Brown can be trusted to serve Baltimoreans when he "won’t even show up in Baltimore to debate."

The Gansler campaign said the 30-second ad started airing in the Baltimore region Thursday and is part of a six-figure ad buy.

Gansler has tried to position himself as the Baltimore candidate in a race in which all of the candidates and their running mates come from the Washington, DC, suburbs. The Montgomery County resident works in Charm City, where the Office of the Attorney General is located.

By the end of the day, the Brown campaign had fired back, releasing an ad attacking Gansler right back. The ad highlights Brown’s plans to expand access to pre-Kindergarten programs and create jobs before pivoting to tape of Gansler that implies he would not do the same. The ad also criticizes Gansler’s plans to cut the corporate tax rate in Maryland. The spot will air in the Baltimore and Washington, DC, markets.

Brown's campaign followed it up in the evening with an email asking supporters to donate to the Brown-Ulman campaign. "Today’s a day that we hoped we wouldn’t see," it reads, and goes on to say that Gansler released the first negative ad of the election.

Todd Eberly, a political science professor at St. Mary’s College, says that while people complain about negative ads, they have proven to be effective time and again. "Negative ads can motivate people to vote against someone, so there is a reason so much money is spent on them."

The third candidate in the race, Del. Heather Mizeur, has released only one TV ad, and it's not a negative one. Eberly says it's not in her interest to go negative because she's positioned herself as one who stays above the fray.

"The truth of the matter is, for her, she’s hoping that these two go after each other to the point that they each succeed in making the other seem unacceptable," Eberly said. "And that might encourage people them to vote for the one person who didn’t play that game."

Jennifer Bevan-Dangel, executive director of Common Cause Maryland, said more negative ads are likely in the offing as the primary looms just a few weeks away. "We’ve got less than a month and this is where people start spending their money and both Brown and Gansler have a huge war chest left. So I think we will see a downward trend from here."

Recent campaign filings show Brown’s campaign with more than $4 million cash on hand, and Gansler’s campaign with over $3 million. Mizeur’s campaign has qualified for matching funds from the state’s public financing system, and reports having about $1 million on hand.

Bevan-Dangel says negative ads are linked to lower voter engagement and turnout, though pundits are already speculating that turnout will be low in this sooner-than-usual primary.