The White House announced the hiring not long after announcing the retirement of lawyer Ty Cobb, who has been the administration's point person dealing with special counsel Robert Mueller's investigation.
Cobb and McGahn hold different views on how cooperative the White House should be with the special counsel investigation. For the first months of this investigation, it was a time to cooperate and turn things over.
"The Failing New York Times purposely wrote a false story stating that I am unhappy with my legal team on the Russian Federation case and am going to add another lawyer to help out".
The latest upheaval of the president's legal team comes as the president has adopted an increasingly hostile posture toward the special counsel, whose investigation has expanded into an examination of whether Trump obstructed justice.
"They told the President that the investigation was going to end originally in November of previous year, then December and then January", Lewandowski told CNN's Jim Sciutto on "The Lead".
"Or if we're going to go in the direction of a subpoena battle, we're ready for that", Giuliani said.
Trump's legal team has been deeply divided on strategy since a year ago, especially on the issue of whether Trump should accept to be interviewed by Mueller, or claim his executive privilege to refuse.
He speculated that an interview could take place in the "beginning of the summer, if that's the direction we're going to go".
Just because Mueller is determined to get Trump's testimony, it does not necessarily mean that he thinks the President is guilty of a crime or an impeachable offense.
Marc Mukasey, a longtime ally of Giuliani, is in talks to possibly join Trump's legal team, according to sources familiar with the matter.
Given the escalating stakes, Trump's tweets on the Mueller probe Wednesday were particularly intriguing.
Trump adds: "At some point I will have no choice but to use the powers granted to the Presidency and get involved!"
The question was tested during the Watergate scandal in 1974, when justices held unanimously that a president could be compelled to comply with a subpoena for tapes and documents.
Last month, former New York City Mayor Rudy Giuliani joined Trump's outside legal team and said at the time that he would communicate with Mueller to bring the probe to an end.
It was not immediately clear in what context the possibility of a subpoena was raised or how serious Mueller's prosecutors were about such a move.
Speaking on the Michael Smerconish show on Sirius XM on Monday, diGenova also said Mueller would be guilty of "outrageous, sophomoric" and "juvenile" behavior if he asked what Trump was thinking when he fired FBI Director James Comey.
"It is no question that it's increased", Toobin said.
Trump meanwhile has stepped up his counterattack.
McGahn and Flood declined to comment.
Two sources told CNN that Cobb was uncomfortable with Trump's tweets against Mueller, with one source describing a "rancid" atmosphere between Mueller and the White House. According to one source, one thing that could keep him in the White House is a Supreme Court retirement - which would give him the opportunity to help shape the court with another conservative jurist - but he could also decide to return to electoral politics in the coming months.