BOSTON (AP) - The casino gambling debate heated up Thursday when Gov. Deval Patrick made a surprise appearance at a Mashpee Wampanoag celebration on Cape Cod, hours after Treasurer Tim Cahill proposed the state enlist private developers to build one or more resort casinos.

But House Speaker Salvatore DiMasi ­- the only one of the three who controls votes needed to expand gambling in Massachusetts - dampened casino talk with a blunt evaluation of Cahill's plan.

"At first blush, I don't think the treasurer has put forward a particularly new, unique or financially sound proposal," DiMasi said in a statement.

Cahill argued the Legislature should vote to expand gambling because Lottery revenues have peaked and Massachusetts residents are spending millions of dollars at the two casinos in Connecticut and slot parlors in Rhode Island.

Cahill said the Cape Cod-based Mashpee Wampanoags will gobble up what could be hundreds of millions of dollars in new revenue for Massachusetts.

"The Wampanoag issue has changed the dynamic," Cahill said. "They're going to be allowed to do this somewhere, somehow, someday, so I think we need to get out in front of it."

The maneuvering came the same day the Mashpee Wampanoags celebrated their official federal recognition as a tribe. Patrick made a surprise appearance and stayed 30 minutes.

Patrick has appointed a task force to examine whether to support an expansion of gaming. He expects a report from the panel this summer.

"Treasurer Cahill has made a reasoned and serious argument, particularly relative to the economic and social aspects of his proposal, and it will be taken into consideration as part of the administration's review," said Kyle Sullivan, the governnor's spokesman.

The tribe has already purchased options on land in Middleborough to possibly open a casino by 2010. The tribe is also considering New Bedford as a site for a casino.

Cahill's plan would involve an auction, open to any developer including the Mashpee Wampanoag tribe, to seek the most lucrative bids. The proposed casino or casinos would be privately owned and operated, but regulated by the state.

The treasurer said state-sanctioned resort casinos could generate up to $1 billion in annual revenue, far more than what the state would get in a pact with the tribe.

But DiMasi said Cahill's plan would hurt the state's negotiating position.

"If we were to consider expanded gaming, one would think it would be a good idea to negotiate with the Indian tribes before we entertain private proposals," he said. "Granting a private expansion of this kind would merely allow the Indian tribes to open similar facilities with absolutely no benefit to the commonwealth."

DiMasi has opposed an expansion of gambling beyond the state lottery and the state's horse and dog tracks. House lawmakers in 2006 rejected a bill designed to allow each of the tracks to install up to 2,000 slot machines.

"The overall question we face as a commonwealth is whether or not we should have expanded gambling in Massachusetts and I don't think there is any change in the House position at this time," DiMasi said.

Senate President Therese Murray, D-Plymouth, has been supportive of expanded gambling. Cahill said DiMasi would be the hardest sell, but Patrick would be receptive because "the governor is looking for more revenue."

Doug Rubin, Patrick's chief of staff and former top lieutenant in Cahill's office, attended Cahill's speech Thursday morning but declined comment.

Tribe spokesman Scott Ferson predicted a "photo finish" on who would be first to build a casino should the Legislature approve expanded gambling.

"To have a constitutional officer endorse the concept that we've been putting forth is encouraging," he said.

Casino gambling opponent Rep. Dan Bosley, D-North Adams, said Cahill's proposal was an "ill-conceived" overreaction to flat lottery revenues. The Wampanoags would soon build a competing casino, he said, and the state's revenues could be eroded further by future projects by other tribes.

Cahill said he knows problems come with casino gambling, such as traffic congestion and more problem gamblers. But he said the benefits - including increased revenue and jobs - outweigh the negatives.

"If we truly wish to compete with our surrounding states for the disposable income of our citizens, and provide relief for property tax owners in every city and town in Massachusetts, we have to remove the constraints around gaming," he said.

AP-ES-05-24-07 1654EDT