Anthony G. Brown kicks off his campaign for governor in Largo in May. (Photo by Astrid Riecken For The Washington Post)

More than a week after Maryland gubernatorial hopeful Douglas F. Gansler asked his Democratic rivals to join him in a pledge to curb outside spending on the race, Lt. Gov. Anthony G. Brown has put forward a counteroffer.

Under Brown’s proposal, the candidates would instead pledge to run positive campaigns and not name one another in negative or misleading ads.

“While I appreciate the intent of Attorney General Gansler’s proposal, frankly I think what Marylanders are most sick of is negative attacks ads, so we’re raising the bar with our ‘Positive Campaign Pledge,’” Brown said Friday.

His proposal was rejected within hours by both Gansler’s campaign and that of a third Democrat in the race, Del. Heather R. Mizeur (Montgomery).

Gansler spokesman Bob Wheelock called Brown’s proposed pledge “a political ploy to avoid standing up to special interests and outside groups” by signing Gansler’s pledge.

Wheelock noted that the Brown campaign employs a “tracker” who films Gansler at public events “hoping to catch some gotcha moments his campaign can then peddle to the media.”

“So, no, we aren’t signing something whose ‘positive’ spirit has already been violated by the Brown campaign months ago,” Wheelock said.

Joanna Belanger, Mizeur’s campaign manager, said that “Heather is already running a positive campaign on the issues and her record.”

She noted proposals put forward in recent weeks to expand subsidized pre-kindergarten education, provide an income tax cut to 90 percent of Marylanders, and legalize marijuana.

“We are focused on ensuring Annapolis works for all Maryland families while our opponents have been engaged in an arms race of political infighting and insider jabs,” Belanger said.

Gansler proposed last week that he and his two Democratic rivals sign a pledge that would discourage independent entities from spending money on television, radio or online advertising that names any of the candidates, or on direct mail that does that.

If such spending occurred, the candidate who benefited would have to pay 50 percent of the cost to a charity chosen by the other contenders.

Under Brown’s proposal, as long as the none of the campaigns ran negative ads, they would also agree to “publicly condemn and ask all third-party groups to refrain from any negative advertisement.”

Legal questions surfaced this week about Gansler’s proposed pledge. Maryland election law bans most charitable contributions by active campaigns.

Gansler’s campaign argued that its version of a pledge could still work because state law allows campaign committees to donate to charities once they have shut down and paid off all other debts.

On Friday, Wheelock said the Gansler campaign would be happy to negotiate another arrangement where money doesn’t go to charity if Gansler’s pledge is adopted and violated.

“We are happy to work out the details,” Wheelock said. “Marylanders deserve to know where you stand.”

Brown probably would have the most to lose if Gansler’s pledge was adopted. His campaign has been endorsed by several labor groups with a history of spending money to help preferred candidates.