NPR's Geoff Bennett joins us now.
The counsel is not required to consult or keep informed the attorney general or deputy attorney generals on the course of the probe.
Rosenstein was on Capitol Hill this afternoon and faced tough questions from senators about the events that led up to FBI Director James Comey's termination and his decision to appoint a special counsel.
In August, Trump said to an enthusiastic crowd that a special prosecutor must take over the investigation into his Democratic rival's emails. But here's the thing.
Many senators said that Rosenstein, who was summoned to the Senate to explain the reasoning for Comey's firing, provided few actual details about the dismissal and his contacts with the White House. "I said, 'There's no place I'd rather be'". Claire McCaskill, D-Missouri, after the briefing.
UNIDENTIFIED MAN: Say that again. "[Rosenstein] learned that Comey would be removed prior to him writing his memo", Sen.
BENNETT: Now, the he that she refers to is the deputy attorney general. Now, Republican Senator Marco Rubio was asked that same question.
The No. 2 Senate Republican, John Cornyn of Texas, said he was supportive of investigations in Congress but expressed concern about the "proliferation" of hearings.
Other senators who attended Rosenstein's briefing said that Rosenstein didn't address who asked him to write the memo.
CORNISH: So help us read between the lines.
Adding to the drama, Comey apparently kept exacting notes and memos describing his private meetings with Trump, evidence that could prove crucial if Mueller's investigation determines there was an effort by the White House - or Trump himself - to obstruct Comey's Russian Federation investigation.
But Trump nearly immediately undermined that explanation in an interview with NBC News, saying, "Regardless of the recommendation I was going to fire Comey". Last week in an interview with NBC's Lester Holt, he claimed he had been planning to fire Comey and called him a "grandstander". What was the president's rationale?
At a joint White House news conference with the President of Colombia, the President also had especially tough words for former Director James Comey, whom he fired just over a week ago, saying Comey was not the right person to lead the Federal Bureau of Investigation. Mueller will have to answer to Rosenstein because the investigation has been classified as "special" and not "independent".
BENNETT: Well, the committee members I've spoken with say they have a different mission entirely.
Mueller's investigation is only to see if criminal wrongdoing occurred. Robert Mueller has a sterling reputation in Washington, DC. Congressional committees can't prosecute. Elizabeth Warren, D-Mass., in asking the Justice Department's inspector general to probe if Attorney General Jeff Sessions was improperly involved in Comey's firing after Sessions recused himself from the Russian investigation. And of course it may not.
In naming Robert Mueller, the United States deputy attorney general said it was in the public interest to pick an outsider.
And now, Mueller is back in Washington DC to investigate "any links and/or coordination between Russian government and individuals associated with the campaign of President Donald Trump, and any matters that arose or may arise directly from the investigation".
Reflecting the fast-moving developments that have engulfed the White House in controversy in recent days, Trump's Thursday news conference and the senators' reactions to the Rosenstein briefing were being broadcast on split screens.