Whitaker was hired as a CNN legal commentator a year ago for several months, before leaving the role in September 2017 to head to the Justice Department as chief of staff to now-former Attorney General Jeff Sessions.
There is some question whether Mr Sessions was sacked or resigned.
The broadsides escalated in recent months, with Trump telling an interviewer that Sessions "never had control" of the Justice Department.
Mr Sessions, who was an early backer of the Trump campaign, recused himself in March 2017 from overseeing the Russian Federation investigation under a similar rule which prohibits officials from overseeing investigations into subjects with whom they have a "a personal or political relationship".
US Attorney General Jeff Sessions was sacked by Donald Trump on Wednesday after enduring more than a year of bitter criticism from the president over his decision to step aside from the Russian Federation investigation that has dogged the White House.
Bondi, who is term-limited as attorney general in the Sunshine State, has always been a Trump ally. Today, he declared victory, taking claim for "Kavanaugh's Revenge" after Democrats failed to win enough seats to have a majority in the Senate.
Several GOP officials in Iowa who have known Whitaker for a long time say they were surprised by his shift in the Trump era. The recusal left the investigation in the hands of Rosenstein, who appointed Mueller two months later after Trump fired then-FBI Director James Comey.More news: Uhuru pushes for more trade with China during Shanghai trip
In fact, Deputy Attorney General Rod Rosenstein's letter appointing special counsel Robert Mueller does not give Mueller broad, far-reaching powers in this investigation.
Clovis, the 2016 Trump campaign national co-chairman, said in a May radio interview that he has been interviewed by the special counsel's team and had testified before the Mueller grand jury.
Dean said despite the ramifications of the Sessions ouster, he has faith in the USA judicial system to survive it.
Trump has made no secret of his feeling about Sessions, calling him a "traitor", a "dumb southerner", "Mr. Magoo" - and, Colbert reminded, Trump called him "perhaps the most humiliating of all: "member of my administration". "It does not take a lawyer or even a former federal prosecutor like myself to conclude that investigating Donald Trump's finances or his family's finances falls completely outside of the realm of his 2016 campaign and allegations that the campaign coordinated with the Russian government or anyone else".
Attorney General Jeff Sessions has resigned as the country's chief law enforcement officer, the Associated Press reports.
And newly elected Utah Senator, Republican Mitt Romney, added that indeed, the Mueller investigation should continue unimpeded.
Sessions also touted the Justice Department's efforts to address crime, immigration, and the opioid crisis, among other issues.
Sessions had been protected for much of his tenure by the support of Senate Republicans, including Judiciary Committee Chairman Chuck Grassley, who had said he would not schedule a confirmation hearing for another attorney general if Trump fired him.