Trump, in a series of morning tweets, reverted back to the tone that won him the White House, slamming the investigation a day after he called for unity in the wake of a shooting at a Republican congressional baseball practice that injured several people, including House Majority Whip Steve Scalise. Justice Department regulations say that a special counsel can be fired by the attorney general "for cause".
Mueller and former FBI Director James Comey worked closely for years in the George W. Bush administration, when Mueller was FBI director and Comey was deputy attorney general.
But expressions of discontent with Mueller are bubbling up nonetheless.
"The chain of command for the special counsel is only directly to the attorney general - and in this case, the acting attorney general", he said.
"Let's just have transparency", Gingrich said, "Could we have as many pro-Trump lawyers as we have anti-Trump lawyers?"
"When I ran, it was make America great again and that is we're doing it", said Trump during a cabinet meeting on Monday. Susan Collins, R-Maine, asked Rosenstein during an open Senate Appropriations subcommittee hearing what he would do if Trump asked him to fire Mueller.
Would there be a Russian investigation if Mueller is fired?
White House frustrations with the Justice Department spilled into public view last week, when Trump on Twitter criticized the legal strategy in defending his proposed travel ban.
White House spokesman Sean Spicer did not explicitly endorse Sessions' appearance, saying in response to a question, "We're aware of it, and we'll go from there".
Republicans in Congress are also shaking off the notion that Trump could fire Mueller.
Rosenstein testified that he is the only one who has the authority to fire Mueller, who was appointed following the May 9 ousting of James Comey as Federal Bureau of Investigation director, and that he had seen no good cause to do so.
Mueller has served multiple presidents in both parties.
But a veritable mountain of circumstantial links has emerged - ranging from Trump's friendship with GOP operative Roger Stone, who has links to Russian hacker Guccifer 2.0, to former national security adviser Michael Flynn, who was sacked for lying to administration officials about a secretive pre-inauguration phone call with the Russian ambassador and was later revealed to have taken Russian money. He said he would agree to dismiss Mueller only if there were a legitimate basis to do so.
High-profile supporters of President Donald Trump are turning on special counsel Robert Mueller, the man charged with investigating Russian interference in the USA election and possible collusion with Trump's campaign. According to the New York Times, sources say the president was only turned off from the idea by staffer who said such an action could "turn a bad situation into a catastrophe", though said sources said the only thing stopping him was the idea the threat of firing Mueller would speak for itself. Still, Gingrich said any special counsel with an agenda can "all of the sudden find something procedural and technical to latch onto".
Ostapenko eager to build on remarkable Roland Garros win
And then, in the third, Ostapenko again summoned a veteran's resolve, taking the last five games after being down a break at 3-1. Last year, she threw a racket during a tournament in Auckland, New Zealand, that bounced off the court and struck a ball boy.
Hometown pleased that student has returned from North Korea
The Department of State, on the orders of the president, secured the young man's release, and he returned home Tuesday. Warmbier also stated that he had been told that if he was detained, a donation of $20,000 would be made to his mother.