WASHINGTON — Former Trump campaign manager Corey Lewandowski slammed “Trump haters” and criticized House Judiciary Committee Democrats for making him appear before their panel — in an impeachment hearing that quickly descended into chaos.

“Sadly, the country spent over three years and 40 million taxpayer dollars on these investigations,” Lewandowski said in his opening statement. “It is now clear the investigation was populated by many Trump haters who had their own agenda — to try and take down a duly elected president of the United States.”

Of the Democrats, Lewandowski said at one point, “I think they hate this president more than they love this country.”

Lewandowski is the first witness hauled before the committee by Chairman Jerry Nadler (D-NY) on the heels of panel members voting to define the scope of their impeachment inquiry. He served as President Trump’s first campaign manager, but has never had an official White House role.

He appeared in the Mueller report, because Trump had asked Lewandowski to deliver a message to then-Attorney General Jeff Sessions telling him to announce that the special counsel’s probe was unfair — and that Mueller should refocus his investigation on future elections.

During the hearing, Lewandowski at one point said he didn’t have Mueller’s words available to him. “I don’t have a copy of the report, Congressman,” Lewandowski told Nadler.

He also refused to answer many of the Democrats’ questions, as White House attorneys told him he couldn’t recount conversations he had with Trump while Trump was serving as president.

Earlier, Nadler had railed against the Trump administration’s instructions.

“The White House has no authority, legally or otherwise, to give these orders,” Nadler said.

The top Republican on the committee, Rep. Doug Collins (R-Ga.), blasted Democrats for holding the hearing in general, calling it a “rerun season.”

That sparring continued throughout.

Nadler and Collins, at one point, bickered over time. A roll call vote was called to stop that fight. A second roll call vote occurred when Collins announced that he wanted the hearing to be adjourned. Later in the hearing, when Lewandowski refused to divulge his conversations with the president, Rep. David Cicilline (D-NJ) suggested the former campaign manager be held in contempt. Nadler said he’d consider it.

When it was Rep. Sheila Jackson Lee’s (D-Texas) turn, she and Lewandowski had a spat over who would read portions of the Mueller report, with some sections being shown on large screens in the room. “You’re welcome to read it, Congresswoman,” Lewandowski said.

“Don’t ask me a question I won’t answer,” Lewandowski told her.

“This is the House Judiciary, not a house party,” Jackson Lee warned Lewandowski at one point.

At the end of her five minutes, Jackson Lee accused Lewandowski of doing the president’s “dirty work in secret because he knew it was wrong.”

Nadler said Lewandowski could go ahead and answer the Texas congresswoman’s question even though her time had elapsed.

“I don’t believe there was a question, Congressman,” Lewandowski said. “Just a rant.”

Lewandowski also poked fun at Rep. Eric Swalwell (D-Calif.) — who already dropped out of the 2020 race — by calling him “President Swalwell.”

Rep. Hakeem Jeffries (D-NY) asked Lewandowski, “Are you the hit man, the bag man, or the lookout or all of the above?”

“I think I’m a good-looking man, actually,” Lewandowski replied.

Lewandowski also couldn’t find the section of the Mueller report that Jeffries was referencing either.