As news broke Monday morning that Deputy Attorney General Rod Rosenstein was resigning or expecting to be fired, Democrats were quick to call for congressional action to protect the special counsel investigation that Rosenstein has managed. 

“With Rosenstein’s departure there is one less barrier protecting the Mueller investigation from President [Donald] Trump’s interference,” Florida Rep. Val Demings said in a statement. “Congress must take immediate steps to uphold the Constitution and the rule of law — which protects all of us — by shielding the Mueller investigation against President Trump’s obstruction.”

California Sen. Kamala Harris tweeted, “The Senate must pass legislation to protect special counsel Robert Mueller TODAY. Republican leaders must allow it to be voted on. We can no longer afford to wait. This is a matter of preserving the rule of law.”

The Senate must pass legislation to protect special counsel Robert Mueller TODAY. Republican leaders must allow it to be voted on. We can no longer afford to wait. This is a matter of preserving the rule of law.

— Kamala Harris (@SenKamalaHarris) September 24, 2018

Other Senate and House Democrats made similar calls on social media and in public statements. 

“It’s very upsetting,” House Judiciary Committee ranking member Jerrold Nadler told CNN of news that Rosenstein was being forced out of the Justice Department. “This is the next step in a slowly evolving, slow motion Saturday night massacre in which the president is getting rid of all the people who were involved in initiating or carrying out the investigation of obstruction of justice by him.”

The New York Democrat said it didn’t really matter whether Rosenstein was fired or resigning.

“If he resigns rather than is fired he’s resigning under great pressure,” he said. “It’s equivalent to the same thing.”

Nadler said he has no knowledge of what’s happening with Rosenstein other than what he’s seen in the news. He said if he were the chairman of the Judiciary panel he would bring Rosenstein in to testify about the circumstances of his departure.

If Rosenstein is fired, “literally everything would be on the table,” Nadler said. He seemed more interested in a building case for obstruction of justice rather than jumping to a need to impeach Trump but he wouldn’t take the latter off the table.

“We don’t know at this point what evidence there will be … but you cannot rule it out,” he said.

Watch: How and Why Many Key Officials Have Exited the Trump Administration

Republicans’ response?

Ultimately congressional action to protect the Mueller probe will depend on Republican leadership, since the GOP controls both chambers of Congress. 

“Paul Ryan, Mitch McConnell, and their Republican colleagues must join Democrats in speaking out and taking IMMEDIATE action to ensure that the Special Counsel’s investigation goes on,” Illinois Rep. Jan Schakowsky tweeted.

Paul Ryan, Mitch McConnell, and their Republican colleagues must join Democrats in speaking out and taking IMMEDIATE action to ensure that the Special Counsel’s investigation goes on. https://t.co/wFkiw3iw7q

— Jan Schakowsky (@janschakowsky) September 24, 2018

Ryan, the House speaker, and McConnell, the Senate majority leader, both support the Mueller probe continuing unimpeded but have said previously that legislation was not needed to ensure that. It was not immediately clear whether the news of Rosenstein’s departure would change their positions. 

Some Democrats want Congress to do more than pass legislation protecting the special counsel investigation. 

“Whether fired or forced to resign, Rod Rosenstein’s ouster will be @realDonaldTrump’s latest attempt to obstruct justice,” Florida Rep. Ted Deutch tweeted. “@HouseJudiciary must convene & hold hearing on obstruction of justice THIS WEEK. The American people demand accountability. The Constitution requires it.”

Whether fired or forced to resign, Rod Rosenstein’s ouster will be @realdonaldtrump’s latest attempt to obstruct justice. @HouseJudiciary must convene & hold hearing on obstruction of justice THIS WEEK.

The American people demand accountability. The Constitution requires it. — Rep. Ted Deutch (@RepTedDeutch) September 24, 2018

Some Democrats weren’t sure how to react to the news yet, since they weren’t sure whether Rosenstein had actually been fired. 

“Trump is either teasing the firing of Rosenstein to distract from [Supreme Court nominee Brett] Kavanaugh implosion, or floating one of his trail balloons to gage public backlash, or it’s really happening,” California Rep. Jared Huffman said in a tweet, urging people to be ready to protest if it is.

It could be today so be registered and ready to protest. Trump is either teasing the firing of Rosenstein to distract from Kavanaugh implosion, or floating one of his trail balloons to gage public backlash, or it’s really happening. https://t.co/XPtuJW5ttK

— Rep. Jared Huffman (@JaredHuffman) September 24, 2018

New Jersey Rep. Bonnie Watson Coleman urged Rosenstein not to resign. 

“If Trump wants to muck-up the Russia investigation, force him to fire you,” she tweeted. 

Rod Rosenstein, in the interest of the independence of the Justice Department you should not resign. If Trump wants to muck-up the Russia investigation, force him to fire you. https://t.co/zChOZSEiP9

— Rep. Bonnie Watson Coleman (@RepBonnie) September 24, 2018

Few Republicans have reacted to the news, although a couple of Trump allies have tweeted about Rosenstein this morning.

“Dep Atty Gen claims ‘just joking’ when he suggested to accomplices he secretly record President, because he and others opposed @realDonaldTrump election and #DrainTheSwamp mandate,” Tennessee GOP Rep. Scott DesJarlais wrote. “But Rod Rosenstein’s name appears on previous FISA application to wiretap President!”

Dep Atty Gen claims “just joking” when he suggested to accomplices he secretly record President, because he and others opposed @realDonaldTrump election and #DrainTheSwamp mandate.

But Rod Rosenstein’s name appears on previous FISA application to wiretap President! — Scott DesJarlais (@DesJarlaisTN04) September 24, 2018

“Why did the Deputy AG of the United States feel it was appropriate to even joke about wearing a wire on the president…while supposed to be overseeing an investigation that obviously involves the president? This is not something to joke about,” Florida GOP Rep. Matt Gaetz tweeted. 

Why did the Deputy AG of the United States feel it was appropriate to even joke about wearing a wire on the president…while supposed to be overseeing an investigation that obviously involves the president? This is not something to joke about. @AmericaNewsroom pic.twitter.com/F4YUZR6uzm

— Rep. Matt Gaetz (@RepMattGaetz) September 24, 2018

Gaetz linked to a Fox News clip in which he said Rosenstein should be called to testify before the Judiciary Committee. If Rosenstein were to decline, Gaetz said he would consider forcing a House floor vote on impeaching Rosenstein. The clip appeared to be taped before the news of Rosenstein’s departure.