Trump blamed the recusal for the appointment of Mueller, who took over the Russian Federation investigation two months later and began examining whether Trump's hectoring of Sessions was part of a broader effort to obstruct the probe.
Up until Wednesday, Mueller's probe into Russian interference in the 2016 presidential campaign had been overseen by Deputy Attorney General Rod Rosenstein, who appointed Mueller days after Trump fired former Federal Bureau of Investigation director James Comey. He has given no indication he believes he needs to step aside from overseeing the probe, according to one person familiar with his thinking, a belief echoed by White House officials.
In a July 10, 2017, appearance on CNN, Whitaker shrugged off the idea that the Trump Tower meeting could be part of a criminal conspiracy.
USA media sources have claimed special counsel Mueller is on the verge of claiming his biggest scalp yet as he readies an indictment against Donald Trump Junior.
Whitaker's selection by Trump as acting attorney general drew sharp criticism from Democratic lawmakers, who described it as an attempt by the president to undermine and possibly end Mueller's investigation.
President Trump and acting attorney general Matt Whitaker.
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Democrats have warned that Whitaker, a Trump loyalist and vocal critic of the probe, may fire Mueller, but he has many other ways to hamper, or even freeze, the investigation.
Whitaker, a former US attorney who worked most recently as Sessions's chief of staff, has publicly criticized Mueller's investigation as too broad.
Whitaker is a former US attorney from Iowa who founded a law firm with other Republican Party activists.
"His most brazen act of obstruction has taken place in the last 24 hours", Clements said.
"The [midterm] election results had barely come in, and Donald Trump railroaded his attorney general into resigning" Wyden said. One associate, Jerome Corsi, said in a video recording Monday that he's "been involved in a really constant basis" for two months with Mueller's investigation. Many of them reflect statutory requirements imposed by Congress, and several may well set substantial restrictions on Whitaker's eligibility to supervise the Mueller investigation due to his prior positions and relationships. "Worth a read", he tweeted.
Trump has repeatedly denied any collusion with Russian Federation, and describes Mueller's investigation as a "witch hunt".
In a statement Thursday, the Republican said Whitaker is a "steady hand that will provide good leadership and judgment, and will ensure that the United States Department of Justice upholds the highest standards of the rule of law".
Moscow denies interfering in the 2016 election.