Republican sources in Iowa who know Whitaker described the onetime tight end for the University of Iowa football team and former U.S. Attorney as a loyal Republican and Trump loyalist.
But the relationship was irreparably damaged in March 2017 when Sessions, acknowledging previously undisclosed meetings with the Russian ambassador and citing his work as a campaign aide, recused himself from the Russia investigation.
But if Mueller is still gathering evidence on other matters such as Trump's business relations with Russians going back before the 2016 election, Whitaker may be able to stifle that, ruling it out of the realm of the original mandate. One was approved by the Senate Judiciary Committee in April, making it eligible for a full Senate vote.
"Dear Mr President, at your request I am submitting my resignation", he wrote in an undated letter.
But a flurry of activity during his quiet period, including weeks of grand jury testimony about Trump confidant Roger Stone and negotiations over an interview with the president, hinted at public developments ahead as investigators move closer to addressing key questions underpinning the special counsel inquiry: Did Trump illegally obstruct the investigation? As acting attorney general, Whitaker will presumably - assuming he has no conflicts of interest - begin overseeing the special counsel's probe.
A personal connection to a Mueller witness is unlikely to sway Whitaker or the White House when it comes to recusal, as Deputy Attorney General Rod Rosenstein supervised the probe despite being a witness himself.
Whitaker has previously questioned the scope of the Mueller probe, writing an opinion column for CNN previous year charging that the investigation would be going too far if expanded to include Trump family finances.
Asked if that would be to dwindle the special counsel's resources, Whitaker responded, "Right".
"If this wasn't about the Mueller probe, why install an Acting AG other than the DEPUTY Attorney General?" he wrote in a tweet.
Dutch businessman, 69, seeks to legally identify as 20 years younger
You're only as old as you feel . "We can make our own decisions if we want to change our name, or if we want to change our gender. Mr Ratelband claims he is discriminated against because of his age and encounters problems in Dutch society on a daily basis.
"Sessions was the worst attorney general in modern American history".
Whitaker so far hasn't said much about his outlook for the Justice Department or the special counsel investigation; Rosenstein hasn't spoken publicly either since Sessions' dismissal.
Some Democrats also considered Sessions too eager to do Trump's bidding and overly receptive to his grievances.
He was the co-chairman of former Texas Gov. Rick Perry's 2012 Iowa campaign for president, and campaigned himself for the Senate seat opened by the retirement of Democrat Tom Harkin. He also announced media leak crackdowns, tougher policies against opioids and his Justice Department defended a since-abandoned administration policy that resulted in parents being separated from their children at the border.
Sessions recused himself from managing the investigation because of his own past involvement in the Trump campaign.
Now Whitaker is in charge of the Justice Department and Rosenstein reports to him, putting Whitaker in a position to constrain the special counsel if he wishes or if he's directed to do so by the president.
"We are immediately issuing multiple letters to key officials demanding that they preserve all relevant documents related to this action to make sure that the investigation and any evidence remains safe from improper interference or destruction", Nadler said.
The Democrats, who won the House in the mid-terms, have vowed to protect it.