Former prosecutor and federal judge John Gleeson, who was appointed by Judge Emmet Sullivan to submit a brief opposing the Justice Department's (DOJ's) motion to dismiss former national security adviser Michael Flynn’s case, recently went public defending Sullivan’s decision not to sign off on dropping the case -- but his own judicial history undermines that position.

In a July 1, 2013, memo and order in the case of U.S. v. HSBC, then-U.S. District Court Judge Gleeson seemed to side with the idea that prosecutors have “near-absolute power” to drop a case.

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“The government has absolute discretion to decide not to prosecute,” Gleeson wrote at the time. “Even a formal, written agreement to that effect, which is often referred to as a 'non-prosecution agreement,' is not the business of the courts.”

Gleeson went on to say that “the government has near-absolute power under [the Federal Rules of Criminal Procedure] to extinguish a case that it has brought." He cited Rule 48(a), which says: “The government may, with leave of court, dismiss an indictment, information or complaint.”

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In a Washington Post op-ed published Monday, Gleeson and two co-authors wrote that the DOJ’s motion to dismiss “is actually just a request -- one that requires ‘leave of the court’ before it is effective.”

That position takes a much softer stance on the prosecution’s power than the one Gleeson had in 2013.

“A court is generally required to grant a prosecutor’s Rule 48(a) motion unless dismissal is ‘clearly contrary to manifest public interest,'" he wrote.

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Now Gleeson indicates that he believes the Flynn case is the rare exception and claims that having amicus curiae ("friend of the court") briefs -- like the one he will be filing -- is just one of "many tools" the court has to serve the public interest.

So far, Sullivan has not appointed anyone to oppose Gleeson's brief.

Fox News' Gregg Re and Jake Gibson contributed to this report.