The US Department of Justice’s bid to dismiss the charges against Michael Flynn, President Donald Trump’s former national security advisor, appears to be a “corrupt and politically motivated favor,” according to a reply brief filed Friday by former federal judge John Gleeson.

Flynn had pleaded guilty to lying to the FBI about communications with a Russian ambassador but later sought to withdraw the plea. The government stated that it wanted to drop the case against Flynn, saying that the lies were not material in the investigation of whether he was an agent of a foreign power.

Gleeson, who has been appointed to oppose the government’s request, wrote in his brief:

To describe the Government’s Motion to Dismiss as irregular would be a study in understatement. In the United States, Presidents do not orchestrate pressure campaigns to get the Justice Department to drop charges against defendants who have pleaded guilty—twice, before two different judges—and whose guilt is obvious.

Gleeson urged the court to deny the government’s motion and sentence Flynn.