SALEM, Ore. (AP) -- A proposed casino re-emerged as an issue in the governor's race Monday when the tribe that runs Oregon's largest casino released a study it says undercuts Gov. Ted Kulongoski's argument for allowing a competing casino at Cascade Locks in the Columbia Gorge.

The Confederated Tribes of the Grand Ronde also launched a TV ad criticizing a gorge casino, although the ads don't mention Kulongoski by name.

In this year's primary election season, the tribe spent nearly $1 million to blanket the airwaves with TV ads blasting Kulongoski and Republican candidate Kevin Mannix.

Kulongoski won the Democratic nomination, despite the ad blitz. But Mannix lost to Ron Saxton in the GOP primary, a loss Mannix blamed in part on the ads. Saxton opposes a gorge casino and thus wasn't targeted.

On Monday, the Grand Ronde released a study seeking to debunk Kulongoski's argument that the Confederated Tribes of Warm Springs will put a casino on a less desirable site on tribal land in Hood River if it isn't allowed to build in Cascade Locks.

The $60,000 study by Golder Associates and Otak Inc. was paid for by the Grand Ronde. It says the Hood River site is not feasible from engineering, environmental or political standpoints.

The $200 million it would take to develop the steeply sloped site exceeds any profits the Hood River casino would generate for the Warm Springs tribe, the report said. Further, it said, the casino would degrade the gorge's environment and has drawn opposition from federal, state and county agencies.

"We do not believe there is a feasible or practical scenario for locating a casino at the proposed Hood River site," said Grant Bailey, a senior consultant with Golder Associates.

Len Bergstein, spokesman for the Warm Springs tribe, attacked the study as a "highly flawed and deliberately deceptive" effort by the Grand Ronde to protect its Spirit Mountain casino against losing its position as closest casino to the Portland market.

Bergstein said the Warms Springs' first choice is the Cascade Locks site, which still needs federal approval, but the tribe is prepared to build on the site east of Hood River, which is already eligible for gambling under federal law.

The tribes have commissioned engineering and architectural plans that call for carving out a steep bluff to form a semicircle around a 75,000-square-foot casino and an adjoining hotel and parking garage, he said.

Kulongoski's endorsement of the Cascade Locks casino has drawn fire from not only the Grand Ronde but also antigambling advocates, state lottery retailers and environmental interests.

They argue that Warm Springs leaders have no intention of building at Hood River and are using that site as a ploy to win approval at Cascade Locks. They also argue that letting the Warm Springs build on nontribal land in Cascade Locks would encourage other tribes to demand they also be allowed to put up casinos in more-profitable, off-reservation sites.

The TV ads the Grand Ronde began airing Monday urge viewers to "tell elected officials" that they don't want a casino in the gorge.

Asked whether the Grande Ronde might begin running ads against Kulongoski before the election if he continues backing the Cascade Locks casino, tribal spokesman Justin Martin said, "That decision hasn't been made yet."

Kulongoski campaign spokesman Anna Richter Taylor said the governor plans to read the Grand Ronde report but has given no indication that he's ready to change his mind - despite the prospect that the Grand Ronde might run ads against him again.

"The governor sets his policies based on the interests of all Oregonians, not just on what one special interest group wants," she said.