The Mashantucket Pequot Indians, who own the Foxwoods casino resort, announced an agreement Tuesday with a New York City landowner and developer to build a $500 million casino-resort on 500 wooded acres in Liberty.

Nineteen miles to the east, in Ellenville, the owners of the long-dormant Nevele Hotel also want to build a $450 million casino-resort, with a golf course, water park and new hotel. And Empire Resorts, which owns a slot machine parlor and horse track in Monticello, wants to move them to the site of another old borscht belt hotel, the Concord, where it would also build a casino-resort.

All three plans would need a change in the State Constitution to allow casino gambling, which is now limited to Indian land.

Promoters have been pushing since the 1970s for the establishment of casinos as a way to revive the Catskills’ resort economy. But the latest round of interest is prompted by Gov. Andrew M. Cuomo’s effort to legalize full-scale casino gambling in the state.

The response to the latest frenzy of proposals, however, has been wary, even in the Catskills, where there is political support for casinos and the jobs and revenue they might bring. Residents, though, have become increasingly skeptical about whether the gambling projects will progress any further than those that failed to materialize before.

“Business is excited, but the average Joe could give two damns,” said Tony Cellini, a casino supporter and the longtime town supervisor of Thompson, where the Concord was. “The people up here are sick and tired about having that golden carrot dangled in front of them.”

The plan by Mr. Cuomo, a Democrat, calls for up to seven casino-resorts. He wants to start with three casinos upstate, including one in the Catskills region, to lift the overall weak economy. He would not permit casinos downstate for five years. The plan would not allow any in New York City, the most sought-after location of gambling companies.

Last year, the Legislature approved a constitutional amendment to allow casino gambling. To become law, the amendment must pass the Legislature again this month and a referendum in the November election. Passage is by no means assured, as legislators debate the details, including locations and tax rates.

The state now has five Indian casinos, and electronic slot machine parlors at nine racetracks.

On Tuesday, the New York Gaming Association, which represents the slot parlors, said that it opposed the governor’s casino plan, saying it would put the parlors out of business and generate far less money for education. The slot parlors, which pay a tax rate of over 60 percent of net slot revenues, generate nearly $1 billion a year for education. Mr. Cuomo has proposed a 25 percent tax rate on full-scale casinos.

State Senator John J. Bonacic, a Republican who represents the Catskills, is advocating for more than one casino in the area.

“I’m focused on the Catskills; that’s where we get the best return for taxpayers and create the most jobs,” Mr. Bonacic said.

In the early 2000s, there were proposals for Indian casinos in the Catskills. Developers bought stretches of land all over Sullivan County. But ultimately little happened. Proponents now say they are closer than ever to building at least one casino in the Catskills. The Mashantucket Pequots also say the Catskills are ideal.

“We think it’s a great location for not only gaming activity, but for a full-scale destination resort, which is what we’d be looking to do,” said Scott Butera, chief executive of Foxwoods Resort Casino.

With revenue down at Foxwoods, in Ledyard, Conn., and more competition on the way in Massachusetts, the Mashantucket Pequots decided to open a new location to increase earnings.

Their proposed casino would go on land owned by the Muss real estate family of New York City, which gained control of the property in the late 1980s.

But developers are also angling for a casino resort at the Nevele. And Empire Resorts recently obtained local approvals to develop a resort and slot parlor on the Concord site. Empire Resorts must build a new racetrack to retain rights for the slots.

Even if casino gambling fails to gain approval, Empire Resorts says it will build the project.