The chairman of a group fighting Maryland's slot-machine referendum threatened yesterday to resign to protest "personal attacks" on Gov. Martin O'Malley made by the campaign and its political figurehead, Comptroller Peter Franchot.

The chairman, electrical union business manager Charles E. Graham, accused Franchot of a "hidden agenda" of personal ambition that Graham said was revealed in the group's latest television ad. The ad echoes arguments Franchot has been making for months.

Less than 24 hours earlier, Franchot - a self-styled rebel among Maryland Democrats - made an early exit from the state party's annual fundraising gala at the Baltimore Hilton hotel. He said he was denied a speaking role because of concerns that he would use the opportunity to rail against the slots proposal that O'Malley backs.

It was the latest act in a months-long political sideshow pitting Franchot against O'Malley and other Democratic leaders, including Senate President Thomas V. Mike Miller. The rivalry has become increasingly barbed as Franchot emerged as the face of the anti-slots movement and O'Malley decided to champion the referendum on the proposal to legalize slots. Miller has been a proponent of slots for several years.

The behind-the-scenes drama comes as Marylanders United to Stop Slots, the ballot committee, is making its final push to derail the slots proposal, which some polls have shown enjoys a wide margin of support. The group, which has raised only a fraction of what the pro-slots ballot committee has received from donors, is urging supporters to donate even small sums to keep a television ad on the air.

It was that 30-second television spot, launched yesterday on Baltimore stations, that prompted Graham to reconsider his position as chairman of Marylanders United to Stop Slots, he said. The ad accuses " Annapolis politicians" of trying to deceive voters and likens the slots proposal to the recent federal bailout of Wall Street. Graham said it appeared to be a campaign commercial for Franchot.

"He's got a hidden agenda, man, and I didn't realize it," Graham said. "What I don't like is the personal attacks that the campaign has taken against the governor and Mike Miller."

Graham's union, the International Brotherhood of Electrical Workers, Local 26, opposes slots out of concern that they will bring poverty and addiction to vulnerable communities, and it was an early donor to the anti-slots ballot committee. The union gave $25,000 in March, a few days after the committee was formed.

Graham said he and the leadership of his union remain opposed to the slots proposal.

He called O'Malley yesterday to express his discomfort with the campaign but said the governor "absolutely did not" encourage him to resign. He also spoke with Franchot and Scott Arceneaux, a senior adviser to the ballot committee, both of whom asked Graham to reconsider his decision, he said.

Arceneaux and Franchot denied making any personal attacks, and they played down the significance of Graham's departure on the campaign's momentum while praising his service.

"It's not a rift at all, and we're fired up and ready to go," Arceneaux said.

The dispute was a "little difference of opinion with the strategy," Franchot said. "I'm sorry if it ruffles a few feathers of powerful politicians in Annapolis."

Graham declined to say whether other members of the ballot committee's steering committee have expressed similar concerns about the tone of the campaign. Although Franchot has frequently used slots-related appearances to criticize O'Malley's policies, Graham said he hadn't noticed the political undercurrent until this week.

But party fissures over slots came to the fore at the Democratic Party gala Monday night that raised $400,000. The event's theme: "Maryland: United for Change."

Quincy Gamble, the party's executive director, said he was the one who recommended that Franchot not be a featured speaker. Both Gamble and party Chairman Michael Cryor said Franchot had raised the divisive slots issue at another party event even though he had been asked not to do so.

"It was my suggestion just to be careful that we stick to the script of unity and make sure everyone is in on the same page," Gamble said.

"I'm sorry he's disappointed," Cryor said. "Life goes on."

Cryor gave a shout-out to elected officials from the podium that night. Franchot's name was met with silence from the several hundred donors and politicians.

Franchot responded by sending a letter to Cryor yesterday, accusing Democratic Party bosses of becoming "indebted to the national gambling industry" and of making a "conscious decision to silence those who are not beholden to these special interests." Ocean Downs Racetrack, which is expected to bid for a slots license should voters approve the proposal, was a gold sponsor of the gala, giving $10,000. Harbor Casino Group donated $2,500.