Acting Attorney General Matthew Whitaker is facing questions of legitimacy, with the state of Maryland filing a motion Tuesday for an injunction declaring his appointment illegal.

The state, in an unpreceded move, filed a motion to challenge the legitimacy of Whitaker's appointment, arguing that deputy attorney general Rod Rosenstein is the rightful acting attorney general and "must be named" as such, according to a press release.

“The Constitution and Congress have established vitally important processes for filling high-level vacancies in the federal government,” Attorney General Brian Frosh said in a statement. "President Trump’s brazen attempt to flout the law and Constitution in bypassing Deputy U.S. Attorney General Rosenstein in favor of a partisan and unqualified staffer cannot stand.”

Whitaker’s appointment has been under fire ever since it was announced last week, coinciding with the resignation of then-Attorney General Jeff Sessions.

SCHUMER THREATENS ADDING MUELLER PROTECTIONS TO SPENDING BILL IF WHITAKER DOESN'T RECUSE HIMSELF

Democrats questioned his qualifications and views on Special Counsel Robert Mueller’s investigation into the alleged collusion between Russia and the Trump campaign, as the head of the Department of Justice is also tasked with the supervision of the probe.

A number of lawmakers called upon Whitaker to recuse from the Russia probe, citing his criticism of the investigation.

Senate Minority leader Chuck Schumer also sent a letter asking why the White House decided to pick “unconfirmed political appointee” as acting top law enforcement official in the county rather than following the statute.

But other legal scholars say Whitaker's appointment is legitimate. Former federal prosecutor and Fox News contributor Andrew McCarthy claims the Vacancies Act allows the president to temporarily fill a position that requires Senate confirmation with any official who’s been in the department for over 90 days.

Whitaker joined the DOJ in October 2017 as Sessions' chief of staff.

An Obama-appointed federal judge in Maryland, Ellen Hollander, will be ruling on who’s the legitimate acting attorney general as part of a lawsuit concerning the Affordable Care Act, or ObamaCare, which sued Sessions in his official capacity, the Times reported.

After Sessions resigned from his post, the judge must name his successor as a defendant in the litigation, essentially ruling who’s in charge of the DOJ.

The Trump administration defended Whitaker’s appointment by also pointing out to the Federal Vacancies Act.

Maryland argues the act applies only to routine positions, not positions such as the U.S. attorney general, and point out to another statute to that specifically says the deputy attorney general is next in line at the Justice Department.