Senator Mitch McConnell (R-KY) is once again set on blocking a congressional investigation into a matter that could be politically damaging to former President Donald Trump and his top lieutenants.

Last week, it was revealed that Trump’s Department of Justice secretly obtained the phone records of Rep. Adam Schiff and Rep. Eric Swalwell, two Democrats from California who were among the most vocal critics of the Trump administration. Their communication records were seized as part of a sprawling investigation into a series of leaks to the news media related to the Trump campaign’s contact with Russians. Records were also secretly obtained from the congressmen’s staffs, family members, and journalists working at CNNThe Washington Post, and The New York Times.

The Inspector General of the DOJ opened up an official inquiry into the use of the secret subpoenas last week, but Democrat lawmakers want key figures from the Trump administration – including former Attorneys General Bill Barr and Jeff Sessions – to testify on the matter before the Senate Judiciary Committee.

But McConnell pushed back, saying:

“Here are the facts: The Department of Justice is empowered to investigate criminal conduct by members of Congress and their staff. Necessarily, this sort of investigation is subject to strict procedural protections. And the department’s inspector general is fully equipped to determine whether those procedures were followed in this case. I am confident that the existing inquiry will uncover the truth. There is no need for a partisan circus here in Congress.”

Not all Republican leaders agree with McConnell. Sen. John Thune (R-SD), the second-ranking member of the GOP leadership, told reporters “Some of the allegations that have been made, I think it needs to be looked at, yeah. The information data that was grabbed from people on the Hill and others. That’s something we need to know. How did they get that information? I assume the committees will work through that.”

Sen. Thom Tillis (R-NC) also seemed open to testimony from Barr and Sessions. “That’ll be a decision ultimately made between the chair and the ranking member. But there are some interesting questions there. But I’ll defer to them on bringing them before our committee,” he said.

Over in the House, Democrats can use their majority to open an investigation without Republican support.

According to The Guardian:

The [House] judiciary committee did not outline concrete steps for their investigation. But [Chairman] Nadler intends to keep the threat of subpoenas hanging over the Trump attorneys general as he ratchets up pressure over the coming weeks, said a source familiar with the matter.