But Trump himself has already said that he was going to fire Comey regardless of any recommendation by the Justice Department.
Rosenstein's decision to bring in a special counsel should bring clarity to whether Trump campaign officials colluded with the Russians, whether the president knowingly ignored advice about Mike Flynn, his first national security adviser, and if he did, why, and whether the president asked now-fired FBI Director James Comey to take a loyalty oath to him and to drop the Flynn investigation.
The president has repeatedly denied any collusion took place, and he did so again Thursday.
Texas Sen. John Cornyn, the number-two Republican in the Senate and a member of its Intelligence committee, said after the briefing that he told Rosenstein he was anxious about the committees stepping on the FBI's toes.
Top House Democrat Nancy Pelosi said an independent commission to investigate the Russian Federation matter was still needed to guard against White House interference.
"There were a lot of questions yesterday about the Rosenstein memo", Mr. Whitehouse, Rhode Island Democrat, said on MSNBC.
What now for President-elect Macron?
But Putin sent his congratulations to Macron in a telegram and called for a renewal of trust between the countries. After her decisive loss, the National Front also geared up for a name change - if not a makeover of its ideas.
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. We trust Mueller to find the truth.
President Donald Trump has hit out at the appointment of a special counsel to lead the Russian Federation probe as "the single greatest witch hunt" in United States history, hours after he said he looked forward to a thorough investigation.
On Thursday, Rosenstein informed the Senate in a closed-door session about Trump's controversial decision to dump Comey. Some said they are uncertain whether the Senate Intelligence Committee investigation will be able to subpoena documents and witnesses, given that Mueller's effort is likely to be seeking the same evidence. But here's something that Republican Senator Lindsey Graham pointed out after the briefing. Bernazzani said if that were to occur, that would be "political suicide". Giving an investigator unlimited independence and resources can lead to rogue prosecutors.
BENNETT: Well, we know from some reporting that Rosenstein wasn't happy about having to shoulder the blame for Comey's firing when the White House initially used his memo as a pretext for it. Mueller's appointment changed that, however; Republican House Speaker Paul Ryan reportedly invited Rosenstein to brief the House of Representatives on Friday.
"I determined that a special counsel is necessary in order for the American people to have full confidence in the outcome", he said. He said Rosenstein's answer wasn't clear.
"In my capacity as acting attorney general I determined that it is in the public interest for me to exercise my authority and appoint a special counsel to assume responsibility for this matter, " Rod Rosenstein said in a statement. So poor in fact that I believe, and you'd have to ask him, because I don't like to speak for other people, but I believe that's why the deputy attorney general went out and wrote his very, very strong letter.