WASHINGTON ― One thing the slow-moving probe into President Donald Trump’s former national security adviser Michael Flynn shows is the remarkable double standard Republicans maintain when it comes to investigating Hillary Clinton, the top Democrat on the House Oversight Committee suggested Thursday.

Rep. Elijah Cummings (D-Md.) was expressing frustration with the lack of Republican cooperation in the investigation into the details of the former general, who quit the national security adviser post early this year after it became clear that he never disclosed payments he received from groups funded by Russia.

“The Republicans are not helping us. You’ve got to understand that. They’re not helping. And they could help,” Cummings told reporters on Capitol Hill.

Cummings’ GOP counterpart, Oversight Committee chairman Jason Chaffetz (R-Utah) has signed letters seeking more information about Flynn.

The intelligence committees in the House and Senate are also looking into Flynn and Trump’s Russia ties but have so far shown little progress.

But GOP leaders have not echoed that effort and Chaffetz has not pushed the issue.

Cummings compared such efforts ― or the lack of them ― to the repeated probes of Hillary Clinton.

There were nine investigations of the 2012 Benghazi, Libya attacks, including the partisan Select Committee on Benghazi. They never found any wrongdoing by Clinton, although the select committee uncovered her ill-advised use of a private email system.

Over the course of those probes, the GOP issued numerous subpoenas, going after people down to the level of Clinton’s tech support guy.

“If they spent one thousandth of the time going after Trump ― President Trump ― that they spent with Hillary Clinton, he’d be in big trouble,” Cummings said.

“When Hillary Clinton was up, going through what she was going through, they were subpoenaing ― every other day. They were holding emergency hearings,” Cummings recalled. “All they’ve got to do is use a little bit of that same effort in this regard.”

Clinton repeatedly testified to Congress over the controversies, including one marathon 11-hour session.

Cummings said he’s asked Chaffetz to call Flynn to testify, and Chaffetz refused.

“I think the American people need to hear from Gen. Flynn. Keep in mind, what his attorney said. He said he’s got a story to tell,” Cummings said. “I am interested to know what that story is. And the implication is he has a lot of information that will help the American people and those looking into this get to the bottom of it.”