Staten Island Republicans won’t be putting the con back into Congress.

Voters on the island decisively rejected ex-Congressman Michael Grimm’s bid to return to the US House in Tuesday’s primary.

Incumbent Rep. Dan Donovan turned back Grimm’s challenge, giving him an overwhelming 28-point margin of victory.

With 90 percent of the precincts reporting, Donovan maintained an insurmountable 64-36 percent lead over Grimm, who is a convicted tax cheat.

Donovan’s win puts a large feather in the cap of the borough’s GOP establishment, which came out hard for the longtime Staten Island pol — and against the convicted-tax cheat.

It didn’t come easy, though: President Trump endorsed Donovan’s campaign in a tweet, former New York City mayor and close Trump adviser Rudy Giuliani hit the trail for the lawmaker and Trump’s son Donald Jr. recorded a robocall that went out to voters there on Monday.