Senate Democrats are quickly running into a GOP buzzsaw as they probe the Trump-era Justice Department’s collection of lawmaker records.

Reports that the Department of Justice (DOJ) under former President Trump obtained lawmaker communications data, and similar info on former White House Counsel Don McGahn, have sparked a days-long fury that’s sent Attorney General Merrick Garland scrambling to contain the fallout.

As part of the fierce backlash from Capitol Hill, Democrats on the Senate Judiciary Committee launched a probe this week and are threatening to subpoena former Attorneys General William Barr and Jeff Sessions if they don’t testify voluntarily.

But that effort faces a significant GOP roadblock since Republicans on the Judiciary Committee will need to back any effort to compel documents or testimony from potential witnesses.

The hurdle for Democrats spins out of their narrow 50-50 majority, which determines the party breakdown on Senate panels.

Approving a subpoena would require either a deal between Senate Judiciary Committee Chairman Dick Durbin (D-Ill.) and Sen. Chuck Grassley (Iowa), the top Republican, or winning over one of the 11 GOP senators on the panel to side with all Democrats to create a majority.

But top Republicans are pouring cold water on the Democratic investigation, underscoring the heavy lift Durbin and members of his caucus face to get bipartisan support to add teeth to the investigation.

Senate Minority Leader Mitch McConnell (R-Ky.) called a pledge by House and Senate Democrats to investigate a “witch hunt in the making.”

“It’s particularly disappointing that our colleagues have taken to attacking former Attorney General Bill Barr over investigative decisions that predated his time at the Department of Justice. Attorney General Barr served our nation with honor and integrity,” McConnell said.

“These latest attempts to tarnish his name bear the telltale signs of a witch hunt in the making,” he added.

Republicans, in part, argue that a congressional probe is unnecessary as the Justice Department Office of the Inspector General starts up its own investigation into the agency’s decisions in 2017 and 2018 to issue subpoenas seeking metadata from House Intelligence Committee Chairman Adam Schiff (D-Calif.) and committee member Rep. Eric Swalwell (D-Calif.) during leak investigations.

McConnell, explaining his opposition to any congressional probes, pointed back to the Justice Department’s own actions.

“Here are the facts: The Department of Justice is empowered to investigate criminal conduct by Members of Congress and their staff,” McConnell said. “And the Department’s Inspector General is fully equipped to determine whether those procedures were followed in this case. … There is no need for a partisan circus here in Congress.”

On the Judiciary Committee, no Republicans have publicly backed subpoenaing either Barr or Sessions.

Grassley appeared more frustrated with the leaking of classified information, which he accused House Democrats of doing for years. The collection of lawmaker records, as well as those of reporters from prominent publications, appears tied to Trump-era investigations into congressional leaks from early in his presidency. 

“I think we’ve got a double standard here,” Grassley said, asked if he would support a subpoena. “Why should I support a double standard?”

Other Republicans were quick to note that Barr has distanced himself from the subpoenas of two House lawmakers’ records, appearing to question what information he or Sessions would be able to provide.

“These are subpoenas that I think are issued well below their level,” said Sen. Lindsey Graham (R-S.C.), a member of the committee.

Sen. John Cornyn (R-Texas), another member of the panel, added: “I saw where he said he didn’t know anything about [it].”

“I’m sure he’ll come without a subpoena, but if Sen. Durbin wants to make a show of it,” Cornyn said.

Judiciary Democrats sent Garland a letter this week formally announcing their investigation and asking for documents related to the subpoenas related to Schiff and Swalwell.

“The Senate Judiciary Committee will vigorously investigate this apparent effort to weaponize DOJ against Trump’s perceived political enemies,” they vowed. 

Durbin acknowledged that he’ll need GOP support to move forward but declined to say what his next steps are.

“You know what the rules are when it comes to Senate subpoenas,” Durbin said. 

Democrats have other options if they hit roadblocks in the Judiciary Committee. The House Judiciary Committee is vowing to move forward with its own investigation. 

“The House Judiciary Committee will investigate the Trump Administration’s surveillance of Members of Congress, the news media, and others. I have instructed my staff to begin that work without delay,” Judiciary Committee Chairman Jerry Nadler (D-N.Y.) announced this week.

Unlike their Senate counterpart, they wouldn’t need GOP support to pursue their own high-profile investigation.

“I’m counting on the House to do their part, and I expect more information from all of this from our new attorney general,” Sen. Mazie Hirono (D-Hawaii), a member of the Senate Judiciary Committee, said about how Democrats could investigate the records collection. 

Hirono appeared skeptical that either Barr or Sessions would testify voluntarily before the Senate. When asked if she thought her GOP colleagues would vote to subpoena either of Trump’s attorneys general, she responded: “I don’t think so.”

The Senate Intelligence Committee could provide another avenue for Democrats to go after Barr and Sessions, but the committee’s leaders are staying on the sidelines for now.

“At this point it’s been mostly Judiciary. I have not had a chance to talk to my committee. ... So far, I’m counting on Judiciary,” said Intelligence Committee Chairman Mark Warner (D-Va.).

Asked if Durbin being unable to get a subpoena would impact his thinking, Warner added: “Let’s not jump ahead.”

“Peace in the valley might break out,” Warner said, “and suddenly Judiciary becomes functional.”