A U.S. appeals court on Thursday instructed the judge presiding over the criminal case against President Donald Trump’s former national security adviser Michael Flynn to respond to a petition in which Flynn asked the appellate court to toss the charges.

The U.S. Court of Appeals for the District of Columbia Circuit gave District Judge Emmet Sullivan 10 days to respond to an emergency petition filed by Flynn’s lawyers seeking to force Sullivan to grant a Justice Department request to dismiss the case.

The department, in a major reversal, on May 7 asked Sullivan to drop the charges, drawing accusations from Democrats and retired career prosecutors that Attorney General William Barr was politicizing the U.S. criminal justice system to go light on Trump’s friends and associates.

A retired Army lieutenant general who also advised Trump’s 2016 presidential campaign, Flynn pleaded guilty in 2017 to lying to the FBI about his conversations with Russia’s U.S. ambassador Sergey Kislyak in the weeks before Trump took office.

Flynn, charged as part of former Special Counsel Robert Mueller’s investigation that documented Russian interference in the 2016 U.S. election to boost Trump’s candidacy, later sought to withdraw his plea and accused the FBI of tricking him. The department’s decision to ask Sullivan to drop the charges followed public pressure from Trump and the Republican president’s political allies.

Sullivan last week signaled reluctance to drop the charges, appointing a retired judge to advise whether Flynn should face an additional criminal contempt charge for perjury. Sullivan has scheduled an in-person court hearing in the case for July 16.

Flynn served as national security adviser in the first weeks of Trump’s presidency before being fired for misleading Vice President Mike Pence about his dealings with Kislyak