U.S. Justice Department, Washington, D.C. (Photo: Mike Scarcella/ALM)

Updated 3:36 p.m. ET

A federal appeals court has no power to appoint a special prosecutor who could challenge the pardon President Donald Trump granted to former Arizona sheriff Joseph Arpaio, convicted on a criminal contempt charge for violating an immigration-related court order, the Justice Department said in a new court filing.

The Justice Department, under U.S. Attorney General Jeff Sessions, is backing Arpaio's push to scrap his conviction. The government's rare position, backing a criminal defendant, spurred the U.S. Court of Appeals for the Ninth Circuit in April to appoint a special prosecutor to defend the Arizona judge who refused to vacate Arpaio's misdemeanor contempt conviction. Trump's pardon, the judge found, did not erase the conviction.

The appeals court is now weighing its power to appoint a special prosecutor in the first place, and any decision to rehear the earlier appointment could clarify the role of any lawyer who is chosen to defend the trial judge.

The Justice Department on Friday urged the court to not intrude on its prosecutorial authority. At most, the government said in its court brief, the appeals court could appoint a friend of the court to defend the trial judge. The government did not take a position on whether the appeals court should appoint an amicus.

"The separation-of-powers concern would be particularly severe if the special prosecutor were able to challenge the validity of the pardon itself," Justice Department lawyers said in their court filing.

In April, a three-judge Ninth Circuit panel divided over the appointment of a special prosecutor. Judges A. Wallace Tashima and William Fletcher concluded the court has the power to appoint a prosecutor under Federal Rule of Criminal Procedure 42.

"Because the United States has abandoned any defense of the district court's decision with respect to vacatur, the merits panel of our court that will decide this appeal will not receive the benefit of full briefing and argument unless we appoint a special prosecutor to defend the decision of the district court," they wrote.

Judge Richard Tallman, voting in dissent, called the court's appointment order "ill-advised and unnecessary."

"I fear the majority's decision will be viewed as judicial imprimatur of the special prosecutor to make inappropriate, unrelated, and undoubtedly political attacks on presidential authority," Tallman wrote. "We should not be wading into that thicket."

In a friend-of-the-court brief filed Friday, The Protect Democracy Project Inc. and several other groups urged the Ninth Circuit not to disturb the panel ruling that appointed a special prosecutor. The panel ruling only resolved "the question of whether anyone will oppose Arpaio's arguments on appeal," attorneys on the brief, including a team from Perkins Coie, said.

"The panel's decision to appoint a special prosecutor was based on the unusual circumstances presented by the government's refusal to continue to prosecute the contempt or to defend its contempt conviction on appeal," Protect Democracy wrote in the amicus brief. "The appointment of a private attorney may have some impact on the parties in this case. But, the fact that another lawyer will now appear to argue a position the United States itself long espoused will have no appreciable effect on any other case or the legal process."

The Justice Department's court brief is posted here:

 

Read more:

Ninth Circuit to Appoint Special Prosecutor in Joe Arpaio's Contempt Appeal

US Justice Dept. Will Back Joe Arpaio in Appeal to Erase Contempt Verdict

Trump's Arpaio Contempt Pardon 'Ends This Prosecution,' DOJ Tells Judge

 

This post was updated to include additional information from a new amicus brief filed Friday.