An upstate New York GOP candidate looking to succeed outgoing Rep. Elise Stefanik is accusing his opponent of illegally dumping dead cattle and debris – as national Democrats start pumping money into the reliably red district in hopes of flipping the seat.

Anthony Constantino called his Dem opponent, Blake Gendebien, a “snob” with an “abusive anti-American temperament” over allegations being levied by an anonymous former employee that the St. Lawrence County dairy farmer illegally dumped tires and dead cattle near a watershed.

“Mr. Gendebien is regularly dumping garbage into a local waterway. This is a violation of multiple state and federal laws,” Constantino claimed at a press conference Monday, before showing aerial photos of tires and other debris snapped by private investigators near Gendebien’s Ogdensburg farm.

“If Blake won’t take care of his land, why would he take care of us?” an ominous voice said over drone footage shown to reporters of the alleged dumping ground.

The attack comes as House Democrats’ campaign arm made a high profile move to add the North Country district to its “Red to Blue” list of potentially winnable races.

The move is rumored to come with a spending plan by national Dems, which would be an indicator that they believe the race – which Stefanik, a Republican, carried with 62% of the vote in 2024 – is within reach.

Cook Political Report recently moved the race from “Solid Republican” to “Likely Republican.”

At Constantino’s discretion, the private investigators filed a report with state police last week and called for a probe into the alleged illegal dumping.

In a sworn statement included in a complaint Constantino’s investigators made to state police, a former employee of Gendebien’s dairy farm also alleged the Dem hired at least one undocumented Mexican migrant before he obtained legal status to work in the US.

That employee, who Constantino’s campaign would not identify, said he was instructed by Gendebien to dispose of dead cows by hauling them over the embankment and into a creek — and saw heaping piles of cow carcasses and junk.

“I estimate approximately twenty to thirty deceased cattle were disposed of there during my employment,” the person wrote in the signed document.

But Gendebien’s campaign told The Post the DEC previously investigated the site after a complaint and “cleared” him.

In a statement, Gendebein accused Constantino of being a “weirdo drone stalking my home and business because he doesn’t know how farming works.”

“I’ve already been cleared here,” Gendebien wrote.

A DEC spokesperson said its officers visited the Democrat’s farm on Sept. 3 and did not find a violation.

Gendebien declared his candidacy for the Stefanik’s New York House seat in early 2025 after the Republican congresswoman was tapped as President Trump’s UN ambassador, before her nomination was pulled.

Asked Monday if he’s worried about national Dems’ interest in the race, Constantino brushed it off as a ploy to jack up their fundraising numbers.

“Every time a story comes out that this race is competitive, the betting markets either remain unchanged or they move more in my favor,” Constantino said, adding Kalshi and Polymarket wagers show him leading the race.

A state police spokesperson confirmed to The Post that they had received Constantino’s complaint and that “the matter remains under investigation.”