The special counsel also has brought charges against Trump's former campaign chair and other campaign figures, along with 25 Russians and three firms accused of meddling in the campaign to help Trump win.
Those words may, in fact, prove prophetic.
Mr Sessions was technically Mr Mueller's boss, but recused himself from the probe to avoid any conflict of interest because he had been an adviser on Mr Trump's election campaign, a decision which led to him falling out of the President's good graces.
Vickie Holt, who ran for the District 48 state House of Representatives seat in Tuesday's election, was at Thursday night's rally.
Bernstein said that operative simply said "Yes".
Protesters held signs reading: "Putin/Trump Make Russia Great Again", "Just when you thought things couldn't get any worse", and "Only guilty men fear the truth".
"Whitaker has publicly outlined strategies to stifle the investigation and can not be allowed to remain in charge of it", Move On said in a statement on its website.
"I just don't understand it because why invite this kind of criticism or scrutiny which you knew it was going to come because of the comments he's made earlier", said Gonzales.More news: Iran's Chabahar Port Scores an India- and Afghanistan-Inspired Sanctions Exemption
An ever-more exasperated Trump ordered him to give up the mic and Acosta refused, with Trump branding him an "enemy of the people" and a "rude, awful person".
Meanwhile, President Donald Trump's legal team has begun working with the president to craft responses to questions from Mueller's team as part of their investigation, sources close to Trump told ABC. Whitaker was hired as a CNN legal commentator past year 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.
So, is the climate fraud investigation screwed with Whitaker in office?
"We can not let this president tell Bob Mueller what to do", Durkan, a former USA attorney, said before leading the crowd in a chant of "Let Bob do his job".
Warner criticized Trump for not appointing a bureaucrat who previously got senatorial confirmation - naming Rosenstein and Solicitor General Noel Francisco. He is a Trump loyalist, once described as the president's "eyes and ears" at DOJ.
Protesters gathered Thursday in cities from NY to California in a warning to the White House not to derail Robert Mueller's probe into Russian meddling in the 2016 USA presidential election.
Whitaker, in a Justice Department statement released on Wednesday evening said, "I am committed to leading a fair department with the highest ethical standards, that upholds the rule of law, and seeks justice for all Americans".
"We're here because we love our country and our democracy and our democracy is at risk", Ewing-Merrill said.
"We are in the lowest of the low times", Samuelian said.
The marches formed a day after Trump fired Sessions, who had recused himself of the investigation into possible collusion between the Trump campaign and Russian government agents.