The nation’s law enforcement agency is under siege, short-staffed because of delays in filling senior positions and increasingly at odds with a president who had already engaged in a monthslong feud with the government’s intelligence agencies.
Several current and former assistant United States attorneys described a sense of listlessness and uncertainty, with some expressing hesitation about pursuing new investigations, not knowing whether there would be an appetite for them once leadership was installed in each district after Mr. Trump fired dozens of United States attorneys who were Obama-era holdovers.
In the five weeks since Mr. Trump fired Mr. Comey, he has let it be known that he has considered firing Robert S. Mueller III, the special counsel leading the Russia investigation. His personal lawyer bragged about firing Preet Bharara, the former United States attorney for the Southern District of New York, who was let go as part of the mass dismissal of top prosecutors. Newt Gingrich, an ally of the president’s, accused Mr. Mueller of being the tip of the “deep-state spear aimed at destroying” the Trump presidency.
Inside the White House, those close to the president say he has continued to fume about the actions of Justice Department officials, his anger focused mostly on Mr. Rosenstein for appointing Mr. Mueller and on Attorney General Jeff Sessions, a longtime political ally whose decision to recuse himself from the Russia case in March enraged Mr. Trump.
What the president wanted out of the investigation was simple, several people close to him said: a public statement that he was not under a cloud. What he got instead were reports of Mr. Mueller’s intention to investigate him for possible obstruction of justice.
An impatient New Yorker by nature, Mr. Trump has been unable in his first months in office to bend Washington to his “you’re fired!” ways. He is frustrated, friends say, and unsure what to do — apart from tweeting, which he views as the most direct and effective way of defending himself and venting his anger.
That anger burst into public on Twitter late Thursday and continued Friday, as the president repeatedly assailed the legal forces arrayed against him. He accused the news media of pursuing a “phony” obstruction story and accused law enforcement and congressional committees of conducting “the single greatest WITCH HUNT in American political history.” He said the investigations are led by “some very bad and conflicted” people.
By Friday morning, his focus was on Mr. Rosenstein, though the president never used his name, and his tweet oversimplified and misstated the truth.
Mr. Rosenstein is supervising the investigation, not conducting it. And Mr. Trump has said he decided to fire Mr. Comey before he received Mr. Rosenstein’s memo.
The outburst came after an oddly worded statement late Thursday from Mr. Rosenstein complaining about news reports based on leaks.
“Americans should exercise caution before accepting as true any stories attributed to anonymous ‘officials,’ particularly when they do not identify the country — let alone the branch or agency of government — with which the alleged sources supposedly are affiliated,” Mr. Rosenstein wrote.
His statement followed two articles by The Washington Post that cited unnamed officials. One said Mr. Mueller’s investigation had widened to include whether Mr. Trump committed obstruction of justice. The other said the investigation was examining financial transactions involving Jared Kushner, the president’s adviser and son-in-law. After Mr. Rosenstein’s statement, The Post updated the article about Mr. Kushner online so that its first sourcing reference was to “U.S. officials.”
The highly unusual statement raised the question of whether Mr. Trump or some other White House official had asked Mr. Rosenstein to publicly discredit the reports. Mr. Trump has repeatedly pushed top intelligence officials to exonerate him publicly.
A Justice Department official, speaking on the condition of anonymity to discuss internal matters, said that no one had asked Mr. Rosenstein to make the statement and that he had acted on his own.
Still, the statement, and Mr. Trump’s tweet, demonstrated the political pressure on the deputy attorney general as the department pursues the Russia probe.
Reaction was swift. Senator Dianne Feinstein of California, the ranking Democrat on the Judiciary Committee, said she was “growing increasingly concerned” that Mr. Trump might attempt to fire both Mr. Mueller and Mr. Rosenstein.
“If the president thinks he can fire Deputy Attorney General Rosenstein and replace him with someone who will shut down the investigation, he’s in for a rude awakening,” she said in a statement. “Even his staunchest supporters will balk at such a blatant effort to subvert the law.”
People close to the president say he is in a firing frame of mind but feels blocked from carrying out such a move because of the potential political damage.
While he has left open the possibility of dismissing Mr. Mueller and began considering it shortly after the special counsel was appointed last month, the president’s anger has been largely trained on Mr. Sessions and Mr. Rosenstein, whom he views less as executors of law than as salaried staff.
At a congressional hearing this week, Mr. Rosenstein issued a modest declaration of independence, testifying that he was the only person who had the ability to fire Mr. Mueller. And he made plain that his actions would not be dictated by the president.
“I’m not going to follow any order unless I believe they are lawful and appropriate orders,” Mr. Rosenstein said. “It wouldn’t matter to me what anybody said.”
Mr. Trump has a different view of the chain of command, aides said, but he also knows that he cannot afford to fire Mr. Rosenstein without prompting a massive backlash on Capitol Hill, even among Republicans. But the deputy attorney general, who would have to sign off on Mr. Mueller’s firing, has become a favorite target for Mr. Trump in conversations with advisers and friends.
The apparent expansion of Mr. Mueller’s investigation into whether Mr. Trump obstructed justice, including by firing Mr. Comey, has raised the question of whether Mr. Rosenstein, a witness to and participant in the events that culminated in that ouster, may also have to recuse himself from overseeing the inquiry.
If he were to do so, or resign or be fired by Mr. Trump, acting attorney general duties for the inquiry would fall to the department’s No. 3 official, Associate Attorney General Rachel Brand.
Ms. Brand has never served as a prosecutor. She advised the Justice Department on selecting judicial nominees under President George W. Bush, and she served as a Republican appointee on the Privacy and Civil Liberties Oversight Board.
“As the deputy attorney general has said numerous times, if there comes a point when he needs to recuse, he will,” said Ian Prior, a Justice Department spokesman. “However, nothing has changed.”
On Friday morning, Mr. Rosenstein reacted in public with the calm of a career prosecutor who had spent nearly three decades in government.
Within an hour of Mr. Trump’s tweet, he addressed a crowd of several hundred people in the Justice Department’s great hall, shaking the hands of 175 government employees, a majority of them assistant federal prosecutors from around the country who had won awards for their work over the past year, including drug and human trafficking prosecutions.
“The pursuit of justice is never a 9-to-5 endeavor,” said Mr. Rosenstein. “I will continue to work alongside all of you to make this department and our country stronger and better.”