The president was referring to the fact that Rosenstein drafted a memo on why FBI Director James Comey should be fired, and that special counsel Mueller is reportedly including the firing of Comey within the scope of his investigation, as an instance of possible obstruction of justice. The new staff - which includes former Enron and Watergate lawyers - came under scrutiny recently for donating to Democrats, CNN reported. "If that happens Mike Pence will soon become the 46th President".
There were several unconfirmed press reports Friday, citing unnamed sources in the Justice Department, that Rosenstein was preparing to recuse himself.
Brand, 44, would only gain that authority if Rosenstein recused himself, but that is becoming a real possibility.
The Democratic National Committee, in a statement Friday, said that Rosenstein, who has authority over Mueller, needs to recuse himself from the Russian Federation investigation and that control of the investigation should not be given to another presidential appointee.
Rosenstein wrote a memo last month noting concerns about Comey's handling of the Hillary Clinton email investigation that the White House initially used to justify the removal of the FBI director.
If Rosenstein were to recuse himself, the responsibility of overseeing the special counsel would fall to the department's third-highest-ranking official, Rachel Lee Brand, who was confirmed a month ago to be associate attorney general.
In addition, Trump has also publicly criticized Rosenstein.
Trump seemed to confirm that story - his White House hadn't denied it but instead condemned the leak from which it sprang - in a Friday morning tweet.
Trump's thinly veiled attack on Rosenstein could be a precursor either to Trump demanding that Rosenstein fire Mueller-which he would likely refuse-or Trump's firing Rosenstein himself.
Democrats and Republicans alike decried President Trump's tweet about the Russian Federation investigation on Capitol Hill Friday. The Comey dismissal could become part of a widening investigation into whether the President tried to interfere with the ongoing Russian Federation probe.
The White House originally pointed to Rosenstein's memo, which was also signed off on by Attorney General Jeff Sessions, when explaining Trump's decision to let Comey go. "He was referencing the Washington Post story from Wednesday night based on anonymous, illegal leaks".
But she lacks any background in criminal law, which would be important if she is charged with taking over the Russian investigation, according to Lawfare. If I'm confirmed to this position, of course, I'll have a very different role.
He's not afraid of the investigation - there is no investigation... there is not an investigation of the president of the United States, period.
A Justice official said Rosenstein was motivated in part because of frustration that recent news stories have unfairly brought on a torrent of "leak" accusations against the Federal Bureau of Investigation and Mueller's team. "Absent the most extreme circumstances, the president would be singularly ill-advised to threaten, much less order, Mueller's firing". "This is just an effort to undermine the credibility of the special counsel". The acting attorney general can also ask for clarification as to why the special counsel made a decision to prosecute someone and can review that reasoning.