Several top Democratic senators on Monday filed a lawsuit against President Donald Trump in a federal court in Washington, DC, over the appointment of acting Attorney General Matthew Whitaker.

The senators — Richard Blumenthal, Sheldon Whitehouse, and Mazie Hirono — accused Trump of violating the Constitution in his appointment of Whitaker, given the Senate was never consulted.

"If allowed to stand, Mr. Whitaker’s appointment would create a road map for the evasion of the constitutionally prescribed Senate advice-and-consent role," the senators said.

Several top Democratic senators on Monday filed a lawsuit against President Donald Trump in a federal court in Washington, DC, over the appointment of acting Attorney General Matthew Whitaker.

The senators — Richard Blumenthal, Sheldon Whitehouse, and Mazie Hirono — accused Trump of violating the Constitution in his appointment of Whitaker, given the Senate was never consulted, and have sued to block Whitaker from serving in the role.

Before Trump elevated him to the position of acting attorney general, Whitaker was the chief of staff for Attorney General Jeff Sessions, a position that does not require the advice and consent of the Senate.

The senators who filed the lawsuit take issue with this, in the sense Whitaker was effectively granted the powers of the office of the attorney general without any say from Congress.

"The constitutional requirement that principal federal Officers be appointed only with the Senate's 'Advice and Consent' ... was adopted by our nation's Founders as an important check on the power of the President," the lawsuit says. "The US Senate has not consented to Mr. Whitaker serving in any office within the federal government, let alone the highest office of the DOJ."

The senators added: "If allowed to stand, Mr. Whitaker's appointment would create a road map for the evasion of the constitutionally prescribed Senate advice-and-consent role."

Trump's appointment of Whitaker sparked concerns the president was trying to undermine the special counsel Robert Mueller's investigation into Russian election interference. Whitaker has publicly criticized the scope of the investigation, which Trump frequently refers to as a "witch hunt."

Whitaker's appointment was controversial also because Sessions' resignation came at the request of Trump, and his departure was announced just one day after the 2018 midterm elections. Trump had long criticized Sessions for recusing himself from the Russia investigation, but there are now calls for Whitaker to recuse himself as well.

Read more: In a 'self-defeating and self-incriminating' slipup, Trump just indicated he installed Matthew Whitaker to kill the Russia investigation

In a recent interview with The Daily Caller, Trump appeared to suggest he tapped Whitaker to be acting attorney general to kill the investigation into Russian election interference.

"As far as I'm concerned, this is an investigation that should have never been brought," Trump told The Daily Caller. "It should have never been had ... It's an illegal investigation."

He then added: "And you know, it's very interesting because when you talk about not Senate confirmed," Mueller "is not Senate confirmed."