President Trump on Wednesday announced that Attorney General Jeff Sessions was stepping down from his post.

His departure puts in jeopardy the special counsel investigation into Russian election interference, which Sessions had recused him.

Asked if new acting Attorney General Matthew Whitaker was taking over oversight of special counsel Robert Mueller’s probe from Deputy Attorney General Rod Rosenstein, a Justice Department spokeswoman said that, “The Acting Attorney General is in charge of all matters under the purview of the Department of Justice.

….We thank Attorney General Jeff Sessions for his service, and wish him well! A permanent replacement will be nominated at a later date. — Donald J. Trump (@realDonaldTrump) November 7, 2018

According to a copy of Sessions’ resignation letter reported by the New York Times and posted by a Los Angeles Times reporter, Sessions was resigning at Trump’s request.

“Dear Mr. President, at your request I am submitting my resignation,” Sessions said in the letter.

Here is the letter, or most of it: pic.twitter.com/UWcYyvdpBd — Del Quentin Wilber (@DelWilber) November 7, 2018

The letter is undated, but the L.A. Times’ Del Quentin Wilbur reported that it was sent to the White House today.

Wow — @kaitlancollins reporting on CNN that Sessions asked Kelly if he could stay until the end of the week and Kelly said no, had to leave today. It’s Wednesday!! — Matthew Nussbaum (@MatthewNussbaum) November 7, 2018

It was expected that Trump’s oft-public scorn for Sessions for his recusal in the Russia investigation would result in Sessions’ removal. It was believed that Trump was waiting until after the midterms to announce any major shake-ups to his cabinet.

It’s unclear what Mueller’s fate will be with Whitaker’s ascension to acting attorney general. Before joining the Justice Department, Whitaker wrote a CNN column accusing Mueller of being “dangerously close” to crossing “a red line in the Russia 2016 election-meddling investigation.”

“If he were to continue to investigate the financial relationships without a broadened scope in his appointment, then this would raise serious concerns that the special counsel’s investigation was a mere witch hunt,” Whitaker said.

Sessions suffered Trump’s ire — which included tweets calling him “beleaguered” and his recusal an “unforced betrayal” — quietly, and only occasionally issued extremely subtle rebukes to the President’s war against the Justice Department for its Russia investigation.

On a cable news hit in 2017, Whitaker also outlined a way a Sessions successor could stymie Mueller’s investigation without terminating the special counsel.

“So I could see a scenario where Jeff Sessions is replaced with a recess appointment,” Whitaker said, “and that attorney general doesn’t fire Bob Mueller, but he just reduces his budget to so low that his investigation grinds to almost a halt.”

Ironically, Sessions was otherwise one of the most able executors of Trump’s hardline agenda among the President’s cabinet. Under his watch, the Justice Department implemented far-right policies on immigration, sought to reverse gains on LGBT equality and women’s reproductive rights, and took a tough, pro-law enforcement stance on criminal justice issues.

Sessions was also one of Trump’s earliest and high profile champions during the 2016 campaign. He was the first senator to endorse Trump and was staple on the campaign trail. Many of his former Senates aides occupy top positions in the Trump administration.

When Trump’s rage at Sessions spilled into public view last year, Senate Republicans signaled that they would not support a move to oust him, and stressed that there was not time in the Senate calendar to confirm his successor. That posture softened in recent months, and Sessions alienated a key ally, Judiciary Chairman Chuck Grassley (R-IA), with his opposition to criminal justice efforts being pushed by the senator.

Sen. Lindsey Graham (R-SC), who is expected to take over the Judiciary chairmanship next year, also defended Sessions vociferously last year, only to water down some of that rhetoric more recently.

“Jeff Sessions served our nation well and honorably as Attorney General. He has dedicated his whole life to conservatism and upholding the Rule of Law,” Graham said in a statement Wednesday after Trump’s announcement. “I look forward to working with President Trump to find a confirmable, worthy successor so that we can start a new chapter at the Department of Justice and deal with both the opportunities and challenges our nation faces.