Gov. Cuomo has placed a lot of his chips on new casinos in New York, but a report out last week confirms the bet won’t pay off.

The Rockefeller Institute study notes that pols nationwide have expanded gambling in hopes of raising new cash with no hit to taxpayers. They also expect casinos to boost local economies.

But history argues otherwise, the report finds. “In the long run,” any growth in gambling revenues “slows or reverses and declines,” it finds. Nor is there any clear proof that economic gains from casinos offset the costs.

Upshot: Pols who want casinos “should weigh the pros and cons carefully.”

Oops — too late for New York: In 2013, Cuomo rammed through a “fix” to the state Constitution that allows seven new casinos here.

The idea wasn’t just to raise cash, but also to revive upstate’s economy, wrecked by years of sky-high taxes and impossible regulations.

That gave Cuomo the pretense of a plan to jump-start upstate — after he’d placed a “temporary” (now permanent) ban on fracking, which would’ve provided a huge boost, as it has across the border in Pennsylvania.

Yet, as the institute’s study shows, gambling is at best a one-time hit of speed: The growth soon slows, and the hoped-for tax revenue and economic boost inevitably fall short.

“State and local government gambling revenues have softened significantly in recent years,” the report finds. Last year, New York’s own take dipped from $3.195 billion to $3.182 billion.

Why? Too much competition — which leaves a smaller slice for everyone.

Look at Atlantic City. It saw four casinos close in recent years as gambling mushroomed in Pennsylvania, Maryland, New York and Connecticut. Today, AC is pretty much bankrupt.

Now, as New York forges ahead with its first four new casinos, Jersey’s thinking of OK’ing gambling right across the Hudson. That’s a sure bet to siphon business from New York’s parlors.

Casinos also impose huge social costs: crime, addiction, personal bankruptcies. Plus, the report notes, much gambling revenue comes from low- and moderate-income people.

Cuomo better have a backup plan for aiding the upstate economy. Gambling, with its dubious benefits and steep costs, is a guaranteed loser.