McConnell, a close Trump ally who said Friday that he talks frequently with the president, insisted that Mueller's investigation into whether the Trump campaign coordinated with Russian Federation in 2016 is not under threat.
Organizers say the naming of Whitaker as Acting Attorney General is a "deliberate attempt to obstruct the special counsel's investigation".
The first was, we have heard leading Democrats, and now many people around the country today, saying Whitaker has to recuse himself because he has clearly expressed he's already made up his mind about Mueller's investigation.
Matthew Whitaker's future at the helm of the Justice Department appeared uncertain at best Friday as President Donald Trump denied even knowing the man he had named acting attorney general just two days earlier. "And [to] put him in this position at Justice to me is somewhat confounding".
He said none of those apply in this case, as Whitaker is not deputy attorney general, he did not receive Senate confirmation for his current role at the DOJ and the Senate is not in recess.
Speaking to reporters at the White House, Trump defended his choice of Whitaker, who has been panned by critics for his past comments on the probe, saying the former US attorney had an excellent reputation and came highly recommended by former Iowa Governor Terry Branstad, who is now Trump's ambassador to China.
The commander in chief pushed back on claims Whitaker should have been confirmed by the Senate.
"I think fundamentally this investigation by Bob Mueller needs to be limited", Whitaker said during an interview with Sean Hannity in 2017.
Whitaker likely could not block the new indictments, which could include Trump's son Donald Jr. "And the people have to speak out as you're doing today".
A replacement for Mueller though would have no such constraints, potentially allowing Trump to hamstring the investigators.
Trump has repeatedly criticized Sessions for that decision, and the Attorney General's dismissal has been expected for a long time.
Thursday's letter to the Justice Department was signed by Oregon's Ellen Rosenblum and Washington's Bob Ferguson and their colleagues in Hawaii, Connecticut, the District of Columbia, Vermont, Rhode Island, North Carolina, California, New Jersey, Minnesota, Illinois, Delaware, New York and MA.
"The Saturday Night Massacre refers to the firing of Special Prosecutor Archibald Cox by President Richard Nixon".