Sen. Elizabeth Warren on Wednesday said the US is watching a "descent into authoritarianism" under President Donald Trump after his attorney general intervened in Roger Stone's case.

"Right in front of our eyes we are watching a descent into authoritarianism," Warren said.

All four prosecutors overseeing the federal government's case against Stone, a longtime informal adviser to Trump, withdrew from the case earlier this week after Barr intervened.

Barr publicly overruled their sentencing recommendation for Stone after Trump complained that it was too harsh.

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Sen. Elizabeth Warren of Massachusetts on Wednesday warned that the country is watching a "descent into authoritarianism" under President Donald Trump.

Warren also called for the resignation or impeachment of Attorney General William Barr after he intervened in the case of a longtime informal adviser to the president, Roger Stone.

The Massachusetts Democrat, who is running for the 2020 Democratic nomination, told CNN's Anderson Cooper that she knows "everybody wants to talk about the horse race" but added that "the thing that is really getting to me right now is what's going on over at the Justice Department."

"The whole notion that we have people in our Justice Department resigning because of Donald Trump's inappropriate influence, and the attorney general overturning a sentencing of Donald Trump's cronies, right in front of our eyes we are watching a descent into authoritarianism," Warren said.

"This just seems like a moment to me everybody should be speaking up," Warren added. "Presidential candidates should be speaking up, people around this country should be speaking up."

The 2020 Democrat expressed similar views in an MSNBC interview:

—All In with Chris Hayes (@allinwithchris) February 13, 2020

Warren's sentiments are shared by experts on authoritarianism and democracy, who have raised alarm bells this week over Trump's actions following his acquittal in his Senate impeachment trial. The president has overseen a purge of impeachment witnesses from the White House and his administration, while his attorney general has intervened in a highly public case of a close associate of the president.

Jason Stanley, a Yale philosophy professor who wrote "How Fascism Works," on Wednesday told Insider: "The Republican Party is betraying democracy, and these are historical times. Someone has got to push back."

"There need to be mass protests," Stanley said, as he called Barr as a "dangerous, authoritarian enabler."

Stone was convicted of seven counts in November, including obstruction of justice, witness tampering, and false statements. The charges related to his communications with WikiLeaks in 2016 and his efforts to prevent a witness in the Russia investigation from testifying to Congress or cooperating with the FBI. Stone was an informal adviser to Trump during the 2016 campaign season and in close communication with the president during that time.

All four prosecutors overseeing the federal government's case against the veteran GOP strategist withdrew from the case earlier this week after top Justice Department officials, under Barr's direction, publicly overruled their sentencing recommendation for Stone.

Trump, who had called Stone's original sentencing recommendation "horrible and very unfair," applauded Barr's intervention in the case.

"Congratulations to Attorney General Bill Barr for taking charge of a case that was totally out of control and perhaps should not have even been brought," the president said in a tweet.

As Democrats push for answers on Barr's intervention in Stone's case, the attorney general on Wednesday accepted an invitation to testify to the House Judiciary Committee on March 31