Partisan tensions are mounting on the Senate Judiciary Committee, with both parties accusing the other of stonewalling.



The panel's investigation into the 2016 election appears to have hit the skids, with members increasingly fighting over the direction of the probe.

Republicans want to dig back into Obama-era scandals, including the FBI’s handling of its investigation into Hillary Clinton Hillary Diane Rodham ClintonButtigieg stands in as Pence for Harris's debate practice Senate GOP sees early Supreme Court vote as political booster shot Poll: 51 percent of voters want to abolish the electoral college MORE’s private email server.



But Democrats say the committee should be focused on potential collusion between President Trump's campaign and Russia, as well as the circumstances of former FBI Director James Comey’s firing.



They are publicly questioning whether Sen. Chuck Grassley Charles (Chuck) Ernest GrassleyCollins says she will vote 'no' on Supreme Court nominee before election The Hill's Morning Report - Sponsored by Facebook - Trump, GOP allies prepare for SCOTUS nomination this week Gardner signals support for taking up Supreme Court nominee this year MORE (R-Iowa), the chairman of the committee, is really willing to look into the Trump administration, including on potential obstruction of justice.



“[Republicans have] walked away from this issue and have tried to divert public attention, sadly, to tell us, 'well let’s go back and investigate Hillary Clinton again,' which is their common refrain. I’m disappointed,” said Sen. Dick Durbin Richard (Dick) Joseph DurbinTumultuous court battle upends fight for Senate McConnell focuses on confirming judicial nominees with COVID-19 talks stalled Senate Republicans signal openness to working with Biden MORE (D-Ill.).



Sen. Sheldon Whitehouse Sheldon WhitehouseHillicon Valley: Murky TikTok deal raises questions about China's role | Twitter investigating automated image previews over apparent algorithmic bias | House approves bill making hacking federal voting systems a crime House approves legislation making hacking voting systems a federal crime LWCF modernization: Restoring the promise MORE (D-R.I.) also pounced on a New York Times story that referenced an anonymous GOP senator saying the president had urged them to open up a separate probe into Fusion GPS — the firm tied to a controversial research dossier on Trump.



“Who is this Republican Senator ‘nudged’ by the White House? Is this why full Judiciary hearings have veered in this direction instead of Russia/obstruction?” he said in a tweet.



Top Democrats on the panel — including Sens. Dianne Feinstein Dianne Emiel FeinsteinBiden leads Trump by 12 points among Catholic voters: poll Names to watch as Trump picks Ginsburg replacement on Supreme Court McConnell says Trump nominee to replace Ginsburg will get Senate vote MORE (Calif), the ranking member — want to subpoena Donald Trump Donald John TrumpOmar fires back at Trump over rally remarks: 'This is my country' Pelosi: Trump hurrying to fill SCOTUS seat so he can repeal ObamaCare Trump mocks Biden appearance, mask use ahead of first debate MORE Jr. for his testimony on a 2016 meeting with a Russian lawyer who promised dirt on Clinton. Democrats also want to know more about Trump Jr.’s contact with WikiLeaks, which published Clinton’s leaked emails.



Sen. Richard Blumenthal (D-Conn.) sent Grassley a letter urging him to subpoena Trump Jr. “immediately.”



Under the committee rules, a subpoena would take either a majority vote of the panel or an agreement between Grassley and Feinstein.



But Grassley appeared to downplay the need for Trump Jr. to publicly testify immediately, stating he was being “fully cooperative” with committee staff and Democrats were still requesting information.



“We need to get what documents [Democrats] need, in order to make a determination [of] if we need to talk to him in an open hearing, but so far, if there’s additional questions, and I understand there is from one of the Democrat members of the committee, I’m willing to cooperate with them and help them get that information,” he said.



Grassley added that he asks Democrats to “take that route first because they need that information in order to make a hearing … successful.”



That answer isn’t likely to sit well with Democrats, who are already concerned about the pace of the Judiciary Committee’s work.



“I think the urgency and pace of our investigation into obstruction of justice and other issues relating to the Department of Justice should be increased,” Blumenthal said when asked about the committee’s overall investigation.



Though Feinstein became the top Democrat on the Judiciary Committee this year, she and Grassley have worked together for years, largely on international narcotic issues. They’ve also publicly praised each other since they started working together on the panel.



Sen. John Cornyn John CornynThe Hill's Campaign Report: GOP set to ask SCOTUS to limit mail-in voting Liberal super PAC launches ads targeting vulnerable GOP senators over SCOTUS fight Senate GOP faces pivotal moment on pick for Supreme Court MORE (R-Texas), a member of the committee, said the current split between the two senators on the 2016 investigation was “to be expected,” but noted that Grassley and Feinstein generally work well together.



“They’re both terrific people and I think on one of the most polarized committees in the Senate, it’s a pleasure,” he said.



Feinstein, who is up for reelection in 2018 and facing a progressive primary challenger, has come under criticism from the left for her work with Grassley. Some also say she hasn’t used her high-profile Senate perch to speak out loudly enough against Trump.



Grassley, meanwhile, has long been respected in Congress for his commitment to congressional oversight.



But tensions have been simmering on the committee’s Russia investigation for months.

Grassley sent a barrage of letters tied to Comey’s firing and Russia’s election meddling without Feinstein, and, separately, appeared to move toward probing the Obama-era Uranium One deal.



Days letter, Feinstein said she would start her own investigation that would focus on potential collusion between the Trump campaign and Russia as well as potential obstruction of justice by Trump.



Since then Feinstein has sent nearly 20 letters, including requests this week for communications director Hope Hicks, former chief of staff Reince Priebus and longtime Trump aide Keith Schiller to agree to an interview with Judiciary Committee staff.



Asked about Grassley’s decision to not sign onto the letters, Feinstein told reporters this week that she believes “there’s an effort … not to go deeply” into the administration.



“And I hadn’t realized it before, but realize it now, and we’re going to have to find a way to deal with it,” she said.



Her comments came after she told NBC’s “Meet the Press” following national security adviser Michael Flynn pleading guilty to lying to federal investigators that what she was “beginning to see is the putting together of a case of obstruction of justice.”

Still, Feinstein hasn't signed onto many of Grassley's recent letters, either, including ones related to the FBI's handling of the Clinton investigation, Fusion GPS or Uranium One. Grassley says he can't compel people to testify without her, and noted Feinstein has specifically told him that she won't help probe Clinton's emails.



Grassley said he believes his committee’s investigation is still bipartisan because both Republican and Democratic staff members are able to participate in the closed-door interviews with witnesses.



“What we generally do, just so you know, there is bipartisan cooperation, is if she wants to submit letters, she submits them to us gives us a period of time to decide do we want to sign on. Sometimes we sign on, sometimes we don’t. We do the same thing [for her],” he said.



He added that, “when we get people up here for questioning, if she has people for questioning, we participate in it, and when we have people for questioning they participate in it. ... So you know the cooperation is going on.”



A staffer, who was standing next to Grassley, added that staffs had interviewed several witnesses just based off letters Grassley sent in October and “there’s a good amount of cooperation.”



Blumenthal, asked if he had concerns about Grassley’s leadership of the panel, also defended the Iowa senator as a “straight shooter.”



“His record shows he is dedicated to uncovering wrongdoing. He’s a great protector of whistleblowers. I’m hopeful that he will be interested in hearing from Donald Trump [Jr.] talk under oath,” he said.



But Grassley also fired back at Democrats on the committee, including Feinstein by name, during a more than half-hour floor speech. He accused them of holding up the committee’s investigation and being unwilling to look into Clinton or Fusion GPS.



"There is a double standard here in the way that they desperately want to go after the president but ignore all other potential wrongdoing in the previous administration," he said, adding that Democrats have “visions of impeachment dancing in their heads.”



He added that the Judiciary Committee, to be credible, has to look both at the FBI's handling of the Clinton email case and Trump’s possible ties to Russia.



"It looks like there was a rush to clear [Clinton]. It looks like the fix was in. I know the Democrats don't want to hear that. ... It stinks to high heaven, but Democrats have visions of impeachment dancing in their heads," he said.



Feinstein declined to respond to Grassley’s speech, saying she hadn’t seen it. But Durbin, asked how Democrats could move around Grassley, admitted they likely couldn’t.



“They’re in control,” he said, “[so] until the majority control changes or their view changes we’re stuck.”