Prevailing In$anity

State lawmakers are looking to make a bad law even worse by expanding the “prevailing wage” mandate. The burden now hits only public-development projects, essentially forcing union wages and union work rules on them. But this measure would extend that to cover private projects that get government benefits — tax subsidies, economic-development grants and so on.

Unions love prevailing wages: Even if they don’t actually hand their members more work, they help disguise the huge costs they impose — a 25 percent premium.

But if this bill passes, any project that’s getting less than 25 percent of its funding from the state will be better off not taking that cash — and may not happen at all.

History lesson: Back in 2009, Bronx Bor- ough President Ruben Diaz Jr. insisted on prevailing-wage rates at a mall planned for the long-empty Kingsbridge Armory. The developer walked, costing 1,200 jobs. The idea that “any job is better than no job no longer applies,” Diaz huffed. The armory still languishes today.

“Extending this wildly expensive mandate” to private projects will “result in less economic development,” 18 wary business groups and builders wrote Gov. Cuomo.

But don’t count on Cuomo to stop this madness: He loves the building-trade unions, and with a White House run on his mind, he’s less worried about what price New Yorkers will pay for a “progressive” victory.

Sadly, some Senate Republicans support the Assembly-passed bill. It’s up to their leaders to quash it.