US Rep. Sean Patrick Maloney defended fellow Democratic Rep. Adam Schiff in the face of blistering attacks from President Trump over the House’s impeachment effort.

“I think the chairman has behaved ethically and professionally at every stage,” Maloney told The Post on Friday evening of the ​House ​Intelligence Committee chairman at the helm of ​the inquiry.

Trump has said Schiff should resign for “treason” for doing a parody of his phone call with the Ukraine president during the impeachment inquiry kickoff hearing.

And Republicans, including moderate GOP Rep. Elise Stefanik of New York, are calling for Schiff to step down as chair for having early knowledge of the whistleblower complaint​ that sparked the impeachment effort.​

But Maloney says Trump and his GOP allies are just “grasping at straws.”

“I don’t think attacking the integrity of Adam Schiff is going to get them very far. He’s a pretty impressive and ethical person who has proved his moral code over a long career,” he said.

Maloney, a Democrat who represents a Hudson Valley district that Trump won in 2016, also backed ​House ​Speaker Nancy Pelosi, who is catching heat for announcing an impeachment inquiry on television rather than through a formal vote on the House floor, as was done for Presidents Richard Nixon and Bill Clinton.

The vote isn’t required and Pelosi has declined to expose a divided House by taking one.

“I’m sure everything won’t be done perfectly. But so far, I think they’ve done a great job. I give them very high marks,” Maloney said of Pelosi and Schiff.

Republicans believe if the House votes to launch an impeachment inquiry it would give them subpoena power and allow Trump’s legal team the right to sit in on depositions and mount a stronger defense.

“Is it their argument that we should take a vote before we know all the facts, because the first set of facts are so damaging?” Maloney said of Republicans.

“I suppose we could, but that would seem unprofessional. And on some level, unfair to the president.”

As a member of the House Intelligence Committee, Maloney is in the thick of the impeachment inquiry​.

He spent all Friday in a secured Capitol room taking testimony from the intelligence community inspector general Michael Atkinson, who received the initial whistleblower complaint that blew open the impeachment inquiry.

“With every new fact that comes out, the president’s conduct looks worse and worse,” Maloney said of the evidence he’s reviewed so far.

A Democrat in a swing district, Maloney didn’t call for impeachment after ​former Special Counsel Robert Mueller’s Russia probe.

But since he learned that Trump asked Ukraine to investigate political rival Joe Biden, Maloney was all in.

“Asking for foreign assistance in an American presidential election is about as serious a presidential offense as you can imagine,” Maloney told The Post. “… It’s flat-out wrong. It’s probably illegal. It is beneath any American president. And we cannot let it go unanswered.”

Almost all Democrats have already said publicly they support an impeachment investigation.

The only New York Democrat holdout is Rep. Anthony Brindisi (D–Utica), who said he needs more facts.

Trump admitted he asked for help from Ukraine to investigate Biden but defended the request as warranted to root out corruption.

“Let’s get all the facts. Let’s be as fair as we should be. Let’s move quickly,” Maloney said of the impeachment inquiry. “And let’s stand to be counted.”