He said none of those apply in this case, as Whitaker is not deputy attorney general, he did not receive Senate confirmation for his current role at the DOJ and the Senate is not in recess.
More alarmingly for Democrats, Mr Whitaker himself had outlined a specific way to stymie the Russian Federation probe. Sessions reportedly resigned at the request of the president.
Christie, a former United States attorney, could face similar calls to the ones Sessions faced to recuse himself from special counsel Robert Mueller's investigation given his role as a prominent 2016 campaign surrogate for Trump.
Here is a look at how Whitaker might stop or slow the Mueller investigation and the risks he might run in doing so.
Can Whitaker be forced to recuse himself?
Under government ethics regulation, federal employees are required to recuse themselves from matters where their impartiality could reasonably be questioned.
For more than a year, Trump has repeatedly attacked Sessions over his recusal from the Russian Federation investigation, saying he wouldn't have installed him in the post had he known he would recuse himself from the probe.
The department's numer two, Deputy Attorney General Rod Rosenstein, took over and appointed Mr Mueller after Mr Trump fired then-FBI Director James Comey in May 2017.
Wendy Williams Worries Demi Lovato’s Living Situation After Rehab ‘Isn’t Stable Enough’
You have to spend time in one place or another, all that time packing bags 3 days a week here, and 3 days a week there'. After 90 days in rehab , Demi Lovato will continue her recovery in a halfway house for three days a week.
For his part, US Senator Cory Gardner, of Colorado, said on Tuesday that he's looking forward to "continuing to work with the President to fulfill his campaign position to leave the regulation of marijuana to the states".
"It is time for Rosenstein, who is the acting attorney general for the purposes of this investigation, to order Mueller to limit the scope of his investigation to the four corners of the order appointing him special counsel", he wrote.
Some Republicans appear to have shared the Democrats' concern over the future of the inquiry, which is being led by Special Counsel Robert Mueller. If Mr Mueller files a report detailing his conclusions, the new acting attorney general could keep the document from ever becoming public.
"I think if you were to ask anyone with DOJ experience they would say 'Huh?"
The investigation has produced 32 criminal charges and guilty pleas from four former Trump aides.
Could a Mueller firing be challenged on legal grounds?
"I'm disappointed in the attorney general for many reasons", Trump told reporters in September. The law was meant to address vacancies created by deaths or resignations, but it is not clear it also applies to those created by firings.
Catherine Herridge reads Sessions's letter of resignation.