WASHINGTON — A federal appeals court agreed to reconsider its ruling that the judge overseeing the criminal case against President Donald Trump's former national security adviser Michael Flynn had no choice but to dismiss it.

The decision to grant a rare "en banc" rehearing before a larger panel of judges revives a case that has raised questions about the independence of the Justice Department under the president. The previous decision, hailed by Trump at the time, was issued by a three-judge panel.

U.S. District Judge Emmet Sullivan in Washington triggered the dispute when he refused to rubber-stamp the Justice Department's surprise May 7 motion to dismiss the case, arguing that he should be allowed to investigate whether it was a politically corrupt effort to help a Trump ally.

The Washington appellate court set arguments for Aug. 11 and said in a one-page order that the "parties should be prepared to address whether there are 'no other adequate means to attain the relief' desired." Sullivan has argued the appeal is premature because Flynn will still be able to appeal if the judge denies the motion to dismiss.

Flynn's lawyer, Sidney Powell, didn't immediately respond to an email seeking comment. Sullivan's lawyer, Washington litigator Beth Wilkinson, declined to comment.

Last month, the divided three-judge panel of the appeals court ordered Sullivan to grant the Justice Department's request to dismiss federal charges against Flynn, who pleaded guilty to lying to the FBI about his contacts with the Russian ambassador in 2016.

Wilkinson said in a court filing that the June order by the appellate panel threatens to "turn ordinary judicial process upside down" because the judge was never given a chance to investigate whether the motion to dismiss was proper.

Sullivan, who was appointed to the bench by Bill Clinton, named a former judge, John Gleeson, as a so-called friend of the court to argue against the government's dismissal of the case. Gleeson issued a blistering June 10 brief that called the government's move "corrupt."

The Justice Department said it was dropping the case because it determined Flynn's false statements weren't "material" to the agents' investigation into Russian interference in the 2016 election. The government also said the FBI agents who Flynn lied to didn't have a proper investigative purpose for interviewing him and essentially set him up to lie — claims repeatedly echoed by Trump, who says the Russia probe was a "hoax."