"I'm extremely troubled that a change may have been made here to stop an investigation, which by all accounts is nearly complete", he said.
The Demorats won several key governor races but failed to win the key state of Florida.
Third, he should immediately obtain a full briefing from Mueller about the scope and direction of his investigation.
In the Senate, statewide Democratic candidates received 50.4 percent of all votes, yet Republicans control 58 percent of Senate seats.
The source close to the Senate Judiciary Committee said that Democrats were unsure whether they would reach out to Republicans to join the lawsuit, but said such a move was "not likely".
The expected chairman of the House of Judiciary Committee said Sunday that Attorney General Matt Whitaker would be first to be summoned early next year in the ongoing Russian Federation investigation.
The myriad questions surrounding Whitaker's independence prompted DOJ veterans and constitutional law experts to lay the groundwork for a legal argument saying Mueller could challenge Whitaker's appointment if he overruled a decision by Mueller.
First Muslim woman elected to House of Representatives
Omar, 36, is a vocal advocate for single-payer health care, tighter gun restrictions and more expansive immigration policies. In 1995, they emigrated to the United States, initially settling in Arlington, Virginia and then moving to Minneapolis.
"You ignored the statutory line of succession", Schumer said in a November 9 letter to Trump. "It's illegal. And it means that anything Mr. Whitaker does, or tries to do, in that position is invalid". "The Justice Department is in good hands during this time of transition". "The president's said repeatedly he's not going to dismiss the Mueller investigation". "I feel certain he will make an outstanding Acting Attorney General!"
Trump said last month he wanted Congress to cut taxes by about 10 percent for middle-income people after the midterm elections, though he has yet to offer specifics. Whitaker will oversee the Mueller investigation.
Whitaker, who is a former US attorney, previously served as Sessions' chief of staff. He added that any attempt to look into the finances of Trump or his family would suggest the probe is a "witch hunt".
In a statement, Justice Department spokeswoman Kerri Kupec said, "Acting Attorney General Matt Whitaker has said he was not aware of any fraudulent activity". In October, President Trump also told Fox News, "Matt Whitaker's a great guy".
Documents show that Acting Attorney General Matt Whitaker was on the advisory board of a Florida company fined $26 million by the Federal Trade Commission; chief intelligence correspondent Catherine Herridge reports.
"Allowing a vocal opponent of the investigation to oversee it will severely undermine public confidence in the Justice Department's work on this critically important matter", the letter said.
After Donald Jr. and Eric Trump (Mikey Day and Alex Moffat) say their goodbyes - and Eric gets confused about the term subpoena (he thinks it's "some penis") - Sessions gets really emotional and starts singing Adele's "Someone Like You" while longingly looking at a picture of Trump (well, Alec Baldwin as Trump). I let it just go on.