He called on Whitaker to recuse himself from the Russian Federation probe because of previous comments about the investigation, echoing calls from other top Democrats.
"Sessions did not do the thing he could have done to better protect Rosenstein, and through Rosenstein, the Mueller investigation", Vladeck said.
Lindsey Graham of SC, a Republican member of the Senate Judiciary Committee and close Trump ally, tweeted that he looked "forward to working with President Trump to find a confirmable, worthy successor". Trump, who denies any collusion, has long complained about the probe, calling it a witch-hunt.
He could also refuse to sign off on a subpoena of Trump if the president refuses to voluntarily speak to investigators.
In April, Pingree co-sponsored House legislation to protect the Mueller investigation by making it more hard for a president to remove a special counsel.
Democrats raised concerns about Sessions' acting replacement, Matthew Whitaker, who now oversees Mueller and once argued Mueller's probe was going too far.
Asked whether Whitaker would take control of the Russian Federation probe, Justice Department spokeswoman Sarah Isgur Flores said, "The acting attorney general is in charge of all matters under the purview of the Department of Justice". Attorney General Elliot Richardson and his deputy William Ruckelshaus resigned rather than comply with Nixon's order.
In a CNN op-ed previous year, Whitaker wrote, "Mueller has come up to a red line in the Russian Federation 2016 election-meddling investigation that he is dangerously close to crossing".
California bar shooter was Marine, had mental health review after domestic disturbance
It was "College Country Night" and two-step lessons were being offered Wednesday at the Borderline, according to its website . Video accessed by the AP showed law enforcement officers and vehicles speeding to the scene and people running from the bar.
The president can not directly fire the special counsel.
FILE - Then-Iowa Republican senatorial candidate and former U.S. Attorney Matt Whitaker is pictured before a televised debate in Johnston, Iowa, April 24, 2014.
Schumer called it "paramount" that Mueller's status be protected by the new attorney general.
"Sessions was the worst attorney general in modern American history".
In that scenario, Mueller's budget could be reduced "so low that his investigation grinds to nearly a halt", Whitaker said during an interview with CNN in July 2017 before he joined the Justice Department.
He found satisfaction in being able to reverse Obama-era policies that he and other conservatives say flouted the will of Congress, including by encouraging prosecutors to pursue the most serious charges they could and by promoting more aggressive enforcement of federal marijuana law. But Trump and his aides are concerned about Mueller's next move with the work that is complete, according to a White House official and a Republican with close ties to the administration. Sessions, having been a part of Trump's campaign, was recused from the matter that involves many members of the president's inner circle.
Jerry Nadler, the top Democrat on the House Judiciary Committee, said he wants "answers immediately" and "we will hold people accountable". Trump's advisers are privately expressing worries that the special counsel, who's been out of the news for the past month, has been stealthily compiling information and could soon issue new indictments or a damning final report.
A copy of Attorney General Jeff Sessions' resignation letter is photographed in Washington on an image of the exterior of the Justice Department.