This article is more than 1 year old

This article is more than 1 year old

Senior Republicans led a chorus of public warnings that the special counsel Robert Mueller must be allowed to continue his Russia investigation after Donald Trump finally fired his attorney general, Jeff Sessions.

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As Trump replaced Sessions with a senior aide, Matthew Whitaker, a critic of Mueller’s inquiry, Senator Susan Collins was among the first Republicans to warn: “It is imperative that the administration not impede the Mueller investigation … Special Counsel Mueller must be allowed to complete his work without interference.”

Mitt Romney, who won the race on Tuesday to become a senator for Utah, aimed his first broadside at Trump, tweeting: “It is imperative that the important work of the Justice Department continues, and that the Mueller investigation proceeds to its conclusion unimpeded.”

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As progressives activated a plan for mass protests across the United States, starting at 5pm on Thursday in all time zones, the former CIA chief John Brennan predicted that it was likely Mueller had already completed his report for the deputy attorney general, Rod Rosenstein, who was yesterday relieved of his duty overseeing the investigation into Russian election interference and any collusion with the Trump campaign.

Brennan told MSNBC: “If there are some major indictments coming down the pike, I wouldn’t be surprised if you’re going to see it very soon. Generally the report that the special counsel will draft and deliver to Rod Rosenstein, I wouldn’t be surprised if that is ready to go.”

Sessions looked close to tears as he was applauded by justice department staff on his way out of the building on Wednesday night.

His departure came hours after he received a White House call ordering him to resign.

He was replaced by his former chief of staff, Matthew Whitaker, who has previously called for Mueller’s investigation to be defunded and reined in.

Trump said in a tweet on Wednesday afternoon that Whitaker had been appointed acting attorney general and that a permanent replacement would be nominated later.

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Whitaker, 49, will take charge of the inquiry into Russian interference in the 2016 election and possible collusion with Trump’s campaign. Sarah Isgur Flores, a justice department spokeswoman, said in an email: “The acting attorney general is in charge of all matters under the purview of the Department of Justice.”

Democrats expressed concern that the president was moving to sabotage Mueller’s investigation, which has obtained guilty pleas to federal criminal charges from Trump’s former campaign chairman, deputy campaign chairman, White House national security adviser and campaign foreign policy adviser.

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Senator Chuck Schumer of New York, the minority leader, said in a statement that Whitaker should recuse himself from the Russia issue in light of “his previous comments advocating defunding and imposing limitations on the Mueller investigation”.

Trump’s decision concluded a long-running public feud between the president and his beleaguered attorney general.

Sessions said in an undated letter to Trump released on Wednesday: “At your request, I am submitting my resignation.” He took credit for reversing a recent rise in violent crime. He was later applauded by staff as he left the department’s headquarters.

“We thank Attorney General Jeff Sessions for his service, and wish him well,” Trump said.

A US official said on Wednesday that Sessions was told he had to resign in a telephone call from John Kelly, the White House chief of staff, rather than Trump himself.

Sessions, a former US senator for Alabama, was one of the earliest supporters of Trump’s presidential campaign, but ran into trouble soon after being confirmed to the new administration.

He enraged Trump by recusing himself in March 2017 from investigations into Russian interference in the 2016 election, following revelations that he had two undisclosed meetings with Sergey Kislyak, then Russia’s ambassador to the US.

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Sessions had not disclosed the discussions when asked under oath during his Senate confirmation hearing in early 2017 about contacts between Trump’s campaign and Moscow. Following his recusal, the deputy attorney general, Rod Rosenstein, took over responsibility for Russia matters.

In May 2017, after Trump fired the FBI director, James Comey, Rosenstein shocked the White House by appointing the former FBI chief Robert Mueller as a special counsel to investigate Russia’s interference and any coordination with Trump’s campaign team.

That investigation has since continued without Sessions being involved, leaving Trump deeply frustrated. Trump has publicly lambasted Sessions for recusing himself, claiming he ought instead to have protected Trump against what the president has termed a “witch-hunt” over Russia. Sessions and Rosenstein have defended Mueller’s integrity.

Whitaker’s view on the investigation appears to be in more line with the president’s. He has publicly proposed choking off funding for Mueller’s investigation and wrote an article for CNN last year declaring that the special counsel was “going too far” and needed to be brought under control.

“The president is absolutely correct,” Whitaker said, after Trump suggested Mueller would exceed his remit by looking into the president’s finances. “Mueller has come up to a red line in the Russia 2016 election-meddling investigation that he is dangerously close to crossing.”

Congressman Jerrold Nadler of New York, the likely new chairman of the House judiciary committee, said the American public “must have answers immediately” on Trump’s reasons for firing Sessions.

“Why is the president making this change and who has authority over Special Counsel Mueller’s investigation? We will be holding people accountable,” Nadler said on Twitter.

Senator Mark Warner of Virginia, the senior Democrat on the Senate intelligence committee, urged senators from both parties to “speak out now and deliver a clear message” to Trump that he must not interfere with Mueller’s investigation.

Legal analysts said that Trump’s decision, announced soon after a lengthy and chaotic post-midterm election press conference at the White House, may set off a long-feared constitutional crisis over the fate of the inquiry, which followed a conclusion by US intelligence agencies that Russia intervened to help Trump win in 2016.

Laurence Tribe, a constitutional law professor at Harvard University, said Trump’s replacement of Sessions with Whitaker was arguably an impeachable offence in itself. “This rule of law crisis has been a slow-motion train wreck for a long time,” said Tribe.

In any case, the firing of Sessions will conclude a bitter public dispute between the attorney general and his president that is unprecedented in recent times.

In August, Trump sharply criticised Sessions in a television interview the day after the president’s former lawyer, Michael Cohen, pleaded guilty to campaign finance violations and his former campaign manager Paul Manafort was convicted of fraud – both cases having stemmed from the Mueller investigation.

Trump said: “I put in an attorney general that never took control of the justice department.”

Sessions struck back with a statement that said: “I took control of the Department of Justice the day I was sworn in … While I am attorney general the actions of the department will not be improperly influenced by political considerations.”