Gambling opponents won a major victory Thursday with Gov. John Baldacci’s announcement he would veto a plan for a statewide referendum on a tribal racetrack casino in Down East Maine.

“Without hard data supporting the claims being set forth by the gambling industry, I cannot, in good conscience, sign this bill,” Baldacci said in a written statement released late Thursday afternoon.

Tribal leaders quickly blasted the governor, who they said was being unduly influenced by wealthy opponents of the plan from southern Maine.

“We recognize we don’t have a friend in John Baldacci. That’s abundantly clear now,” said Passamaquoddy Tribal Rep. Fred Moore, who repeated his intention to pursue a citizen-initiated referendum in November 2006.

“He vetoed it because he didn’t want to be overridden by the people,” Moore said, contending his plan, which won widespread backing in the Legislature, had similar public support. “We’ll put it on the ballot right next to his name and see what happens.”

Moore’s bill, LD 1690, would have allowed a statewide vote in November 2005 on whether to place as many as 1,500 slot machines at a new harness racing track on or near the Passamaquoddy reservations near Calais and Eastport.

The Passamaquoddy Tribe would run the horse track, and its proceeds would be distributed to Maine Indian tribes, county development programs and funds benefiting the harness racing industry and college scholarships.

Two weeks ago, Baldacci vetoed an almost identical plan, LD 1573, without the referendum requirement, saying casino-style gambling, despite its allure, would not bring much-needed economic development to Washington County. The House of Representatives later sustained the veto.

The slots plan was revived, however, after Baldacci indicated he would support a statewide referendum on the issue if the idea could win a two-thirds vote in both the House and Senate.

While the House narrowly met the threshold, the Senate did not, falling one vote – or, more precisely, one percentage point – short of the two-thirds majority in its 21-11 vote.

In his statement Thursday, Baldacci cited the Senate vote as a factor in his decision and noted that supporters of the plan could bring it to the ballot themselves through the citizen initiative process.

“I will not stand in the way of any future effort that places the issue of expansion of casino gambling before the voters,” Baldacci said.

Although announcing his intention to veto the bill, technically Baldacci will return the bill to the Legislature when it reconvenes, possibly sometime next month. Lawmakers could then opt to override the veto with the support of two-thirds of voting members in both chambers.

Moore’s bill is based on existing law allowing as many as 1,500 slot machines at Bangor Raceway, the only site eligible to host the state’s newest form of gambling. Maine voters in a 2003 referendum favored allowing slots at harness racing tracks as long as local voters approved.

Opponents of the Passamaquoddy plan, which would double the number of slots in Maine, were pleased with Baldacci’s veto but braced for future efforts to expand gambling in the state.

“There’s so much money behind efforts to open up casino-style gambling to new territory, and Maine is new territory,” said Valerie Landry, spokeswoman for the Portland based CasinosNO! “We will be here for the next effort and the one after that.”