Judge Emmet Sullivan's decision to allow third parties to submit amicus curiae ("friend of the court") briefs in former national security adviser Michael Flynn's case after the Justice Department moved to dismiss it has struck legal experts as "unusual," if not "outrageous," while Flynn's own counsel argues that it should not be allowed in the first place.

The DOJ agreed to drop the charges against Flynn last week, but Sullivan has to sign off on it in order for the case to go away. Sullivan's order Tuesday shows he is not ready to do this just yet.

FLYNN JUDGE TO ALLOW 'AMICUS' SUBMISSIONS, DELAYING IMMEDIATE RESOLUTION AND DRAWING PLANNED ETHICS COMPLAINT

“This is an outrageous decision by a judge who’s now placed himself into that, you know, awful category of an activist who’s willing to set aside rules, set aside ethics, set aside precedent, and just go in a direction because he is politically motivated to do so," former Utah U.S. Attorney Brett Tolman told "Fox & Friends" Wednesday morning.

Flynn's attorney Sidney Powell wrote in a court filing following Sullivan's order that there is no local rule allowing for amicus briefs in criminal cases.

"A criminal case is a dispute between the United States and a criminal defendant. There is no place for third parties to meddle in the dispute, and certainly not to usurp the role of the government’s counsel," Powell wrote.

Powell pointed out to Fox News that when Obama administration Attorney General Eric Holder asked Sullivan to dismiss the case against then-Senator Ted Stevens, R-Alaska, and vacate the conviction, Sullivan not only acceded, but he criticized the DOJ for prosecutorial misconduct.

National security attorney Brad Moss offered a more diplomatic view of Sullivan's decision, but recognized that it is still an unorthodox decision.

"It is rather unusual for this to occur in a criminal case, as the need for amici is usually only warranted in civil cases," Moss told Fox News, "but Judge Sullivan is known to have an unconventional streak."

Unlike Tolman, who claimed that Sullivan was motivated by political activism, Moss suggested that in light of the controversy over the DOJ's decision to drop the case against a former Trump administration official, the judge wanted additional voices to weigh in on the matter "to reassure the public that there has been fair and impartial justice administered here."

OBAMA KNEW DETAILS OF FLYNN CASE, SHOCKING TOP DOJ OFFICIAL, DOCS SHOW

Judge Sullivan himself acknowledged that the local criminal procedure rules do not provide for third parties to file amicus briefs in criminal matters, but he claimed that the local rules governing civil cases -- which do allow for amicus briefs -- "govern all proceedings in the United States District Court for the District of Columbia."

George Washington University Law Professor Jonathan Turley called Sullivan's order an "interesting development" that "certainly does not suggest quick order granting an unopposed motion."

Turley went on to add that he does not believe that amicus briefs will ultimately impact how the case is resolved.

"Amicus can certainly add more heat but not light," he said. "More importantly, it is unlikely to change the outcome."

CLICK HERE FOR THE FOX NEWS APP

Flynn first reached an agreement in 2017 to plead guilty to providing a false statement to investigators in the FBI's Russia investigation. Sentencing was delayed as he cooperated with prosecutors, but after bringing on Powell as his attorney Flynn pushed back against the FBI and sought to withdraw the plea. After evidence was unsealed that showed the FBI may have been trying to get Flynn to lie when they investigated him, the DOJ agreed to drop the case.

DOJ spokesperson Kerri Kupec told Fox News Tuesday that the department's decision to move for dismissal was motivated by "a duty to correct" past wrongs.

"Knowing what we now know, we believe this case should never have been brought," Kupec said.

Fox News' John Roberts contributed to this report.