It’s not a common practice - basically the judge is saying that the DOJ is no longer representing the interests of the people of the United States so someone else has to step in. That’s how corrupted it has become under Barr.U.S. District Court Judge Emmet Sullivan did not immediately grant the DOJ’s motion to dismiss its case. Instead, he appointed a former federal judge to argue against the request, and submitted a schedule to allow third parties to submit arguments in the case.
Is this a common practice? It seems as though the judge has appointed another prosecutor and is inviting third party comment on the case.