Congress needs “to be focused on what our role is,” said Senator John Cornyn, Republican of Texas and a member of the Intelligence Committee. “We’re not the F.B.I. We’re not the Department of Justice. We’re conducting oversight investigations and that’s, I think, our appropriate role.”
Senator Lindsey Graham, Republican of South Carolina and a member of the Judiciary Committee, said, “You’ve got a special counsel who has prosecutorial powers now, and I think we in Congress have to be very careful not to interfere. Public access to this is probably going to be very limited now. It’s going to really limit what the public will know about this.”
For Congress, the appointment of a special counsel means “you’re pretty well knocked out of the game,” Mr. Graham said. “And that’s probably the way it should be.”
The abrupt shift in priorities poses a challenge for Democrats, who were almost united in their call for a special counsel, but now face losing access to their most potent political weapon: public hearings, where Americans could hear firsthand from officials with concerns about Mr. Trump’s administration.
It was at a congressional hearing in March that Mr. Comey first publicly acknowledged that the bureau was running a broad counterintelligence investigation into Russian interference. And at a hearing this month, Sally Q. Yates, the former acting attorney general, explained how she had warned the White House that Michael T. Flynn, the former national security adviser, could be vulnerable to blackmail by the Russians.
Mr. Mueller’s new grip on the investigation also called into question whether Mr. Comey would accept any of the invitations issued by multiple congressional committees to testify next week about his firing. The testimony was widely anticipated as a chance for Mr. Comey to discuss a memo he wrote that said Mr. Trump asked him in February to drop the investigation of Mr. Flynn, an assertion Mr. Trump emphatically denied on Thursday.
Senator Ron Johnson, Republican of Wisconsin, said he believed it would be more difficult for lawmakers to get information now.
“I think Democrats probably should be asking themselves, sometimes you’ve got to be careful about what you ask for,” he said. “Because when you get it, all of a sudden you can’t get answers to things because now it’s an active investigation.”
Democrats appeared to share that concern as they trickled out of the roughly 90-minute briefing, describing Mr. Rosenstein’s reticence to answer many questions. Several senators and aides said the meeting was contentious, and “most of the questions and indeed almost all the very challenging ones came from Democrats,” said Senator Richard Blumenthal, Democrat of Connecticut.
“Basically any question of any substance, it was,…