U.S. Attorney Matthew Whitaker speaks during a news conference as James Vandenberg, Office of Inspector General for the Dept. of Labor, left, and Iowa state Auditor David Vaudt, right, look on, Tuesday, Jan. 16, 2007, in Des Moines, Iowa.  A federal grand jury on Tuesday returned a 27-count indictment against five people in a Des Moines area job training agency pay scandal.
Charlie Neibergall/AP
U.S. Attorney Matthew Whitaker speaks during a news conference as James Vandenberg, Office of Inspector General for the Dept. of Labor, left, and Iowa state Auditor David Vaudt, right, look on, Tuesday, Jan. 16, 2007, in Des Moines, Iowa. A federal grand jury on Tuesday returned a 27-count indictment against five people in a Des Moines area job training agency pay scandal.
Now playing
02:35
Sources: Whitaker has no plans to recuse himself
stacey abrams john kennedy split
POOL
stacey abrams john kennedy split
Now playing
07:39
'Ok, I get the idea': GOP senator cuts off Stacey Abrams on controversial voting law
CNN
Now playing
03:10
Weir on Biden's vow to cut emissions: It's incredibly hard
Now playing
03:05
Was QAnon used by foreign adversaries?
CNN
Now playing
01:28
Buttigieg: It's going to take a national effort to reach Biden's climate goal
Sen. Lisa Murkowski (R-AK) speaks to reporters as she arrives for the continuation of the Senate impeachment trial of President Donald Trump at the U.S. Capitol on January 29, 2020 in Washington, DC. The next phase of the trial, in which senators will be allowed to ask written questions, will extend into tomorrow. (Photo by Mario Tama/Getty Images)
Mario Tama/Getty Images
Sen. Lisa Murkowski (R-AK) speaks to reporters as she arrives for the continuation of the Senate impeachment trial of President Donald Trump at the U.S. Capitol on January 29, 2020 in Washington, DC. The next phase of the trial, in which senators will be allowed to ask written questions, will extend into tomorrow. (Photo by Mario Tama/Getty Images)
Now playing
04:08
Murkowski explains why she's voting for Biden nominee
President Joe Biden, accompanied by Vice President Kamala Harris, speaks Tuesday, April 20, 2021, at the White House in Washington, after former Minneapolis police Officer Derek Chauvin was convicted of murder and manslaughter in the death of George Floyd. (AP Photo/Evan Vucci)
Evan Vucci/AP
President Joe Biden, accompanied by Vice President Kamala Harris, speaks Tuesday, April 20, 2021, at the White House in Washington, after former Minneapolis police Officer Derek Chauvin was convicted of murder and manslaughter in the death of George Floyd. (AP Photo/Evan Vucci)
Now playing
03:01
'A step forward': Biden speaks after Chauvin's guilty verdict
CNN's Eli Honig explains how much time former police officer Derek Chauvin, 45, could face after he was convicted of second-degree unintentional murder, third-degree murder and second-degree manslaughter in the case of George Floyd.
CNN
CNN's Eli Honig explains how much time former police officer Derek Chauvin, 45, could face after he was convicted of second-degree unintentional murder, third-degree murder and second-degree manslaughter in the case of George Floyd.
Now playing
03:25
Here's the sentence Derek Chauvin could face after guilty verdict
CNN's Van Jones reacts to Attorney General Merrick Garland's announcement that the Justice Department has launched a federal civil probe into policing practices in Minneapolis following the death of George Floyd and the murder convictions for ex-cop Derek Chauvin.
CNN
CNN's Van Jones reacts to Attorney General Merrick Garland's announcement that the Justice Department has launched a federal civil probe into policing practices in Minneapolis following the death of George Floyd and the murder convictions for ex-cop Derek Chauvin.
Now playing
03:08
Van Jones reacts to Justice Department's Minneapolis police probe
CNN
Now playing
03:14
'Performative outrage': Avlon on GOP backlash to Rep. Waters
Two Honduran children found clinging to an island surrounded by a powerful current in the Rio Grande were rescued by Border Patrol agents and taken into custody, the region's top border official said, the latest example of the dangers migrants face as a growing number desperately attempt to reach the US.
U.S. Border Patrol
Two Honduran children found clinging to an island surrounded by a powerful current in the Rio Grande were rescued by Border Patrol agents and taken into custody, the region's top border official said, the latest example of the dangers migrants face as a growing number desperately attempt to reach the US.
Now playing
02:22
See Border Patrol rescue 2 migrant children in Rio Grande
Biden speaks from the Treaty Room in the White House on April 14, 2021 in Washington, DC.
Andrew Harnik/Pool/Getty Images
Biden speaks from the Treaty Room in the White House on April 14, 2021 in Washington, DC.
Now playing
02:59
Enten: Biden is focused on what Americans care about
CNN
Now playing
02:40
Biden says he's praying for 'right verdict' in Chauvin trial
ST. PAUL, MN - NOVEMBER 6:  Former U.S. Vice President Walter Mondale concedes the election to his Republican opponent Norm Coleman November 6, 2002 in St. Paul, Minnesota. Mondale and Coleman were in a race for U.S. Senate that was too close to call the evening before.  (Photo by Mark Erickson/Getty Images)
Mark Erickson/Getty Images
ST. PAUL, MN - NOVEMBER 6: Former U.S. Vice President Walter Mondale concedes the election to his Republican opponent Norm Coleman November 6, 2002 in St. Paul, Minnesota. Mondale and Coleman were in a race for U.S. Senate that was too close to call the evening before. (Photo by Mark Erickson/Getty Images)
Now playing
03:00
Walter Mondale dies at 93
george w bush congress immigration rhetoric cbs intv sot mxp vpx_00000000.png
george w bush congress immigration rhetoric cbs intv sot mxp vpx_00000000.png
Now playing
01:25
Bush calls on Congress to tone down 'harsh rhetoric' on immigration
WASHINGTON, DC - MARCH 23: Sen. Ted Cruz (R-TX) speaks at a Senate Judiciary Committee hearing on "Constitutional and Common Sense Steps to Reduce Gun Violence" on March 23, 2021 in Washington, DC.  Many senators spoke both for and against gun control the day after a shooting in Boulder, Colorado where a gunman opened fire at a grocery store, killing ten people. (Photo by Tasos Katopodis/Getty Images)
Tasos Katopodis/Getty Images
WASHINGTON, DC - MARCH 23: Sen. Ted Cruz (R-TX) speaks at a Senate Judiciary Committee hearing on "Constitutional and Common Sense Steps to Reduce Gun Violence" on March 23, 2021 in Washington, DC. Many senators spoke both for and against gun control the day after a shooting in Boulder, Colorado where a gunman opened fire at a grocery store, killing ten people. (Photo by Tasos Katopodis/Getty Images)
Now playing
03:18
Berman on Cruz's latest tweet: 'The pot calling the kettle violent'
(CNN) —  

Three presumptive Democratic committee chairman on Thursday outlined on a call for Democratic lawmakers the steps they’re planning to take to investigate the firing of Attorney General Jeff Sessions and protect special counsel Robert Mueller’s investigation following the appointment of acting Attorney General Matt Whitaker.

On the call for current and new Democrats, organized by Minority Leader Nancy Pelosi, the likely incoming Judiciary Chairman Jerry Nadler of New York said it was a “crisis moment” they had to address, according to a source familiar with the call.

Two sources said that Nadler, presumptive Intelligence Chairman Adam Schiff of California and presumptive Oversight Chairman Elijah Cummings of Maryland spoke to explain the steps they had already taken since Whitaker’s appointment, including directing numerous agencies to preserve documents in the Mueller investigation and related to Sessions’ firing.

The letters, which signaled that Democrats plan to investigate the ousting when they’re in the majority next year, were the “first move” to protect Mueller from being fired, Schiff told CNN’s Jake Tapper on Thursday.

One source on the call said the Democratic speakers laid out the case for rank-and-file lawmakers so they “all understood in common terms how grave of a mistake” it was for Trump to have fired Sessions.

The Democratic committee leaders also said they’re going to try to push Republicans to include legislation to protect the special counsel in the spending bills that must be passed in December, as well as measures that would preserve documents, according to a Democratic aide.

Nadler said on CNN’s “Erin Burnett OutFront” Democrats could make a bill protecting Mueller’s independence a “condition of passage” to fund the government next month.

Nadler said Democrats “could insist that (the bill) be a condition of passage of the remaining legislation to fund the government, which has to be done by December 7.”

“So, you could – you’re going to hold it hostage?” CNN’s Kate Bolduan asked the New York Democrat.

“I wouldn’t call it holding hostage,” Nadler said, but said he thinks the “future of constitutional government is at stake,” and “we must go a long way to make sure that the President is a president, not a king.”

The Democrats argued that Whitaker, who has been publicly critical of the Mueller investigation, was appointed for the sole purpose of protecting the President and obstructing the Mueller investigation, the aide said.

They’ve called for Whitaker’s recusal over conflicts of interest in the Mueller investigation, and say his appointment is part of a pattern from President Donald Trump to ultimately end the Mueller probe, according to the aide.

Nadler told Bolduan that Whitaker is “not fit” for the role “because he’s expressed very negative opinions of the investigation.”

“He’s prejudged – he’s said there was no crime, there was no interference by the Russians in the election, which we know is ridiculous,” Nadler said. “All our intelligence agencies say the contrary.”

The committee leaders also discussed the legal arguments that have been made that Whitaker’s appointment is unconstitutional because he hasn’t been confirmed by the Senate for any position, though Democrats are still mulling what steps, if any, might be taken, one source said.

Nadler told his Democratic colleagues that danger to the special counsel investigation wasn’t just that Mueller could be fired outright — it was also that smaller but still harmful actions could be taken by Whitaker — or Republicans in Congress during the lame-duck session, the source said.