A federal judge on Sunday denied former Trump campaign foreign policy adviser George Papadopoulos’ motion to stay his 14-day prison sentence pending a separate constitutional challenge to special counsel Robert Mueller’s authority.

“Papadopoulos has failed to carry his burden of demonstrating that a delay in the execution of his sentence is warranted,” Judge Randolph Moss wrote.

Papadopoulos is due to report to prison Monday.

Special counsel Robert Mueller on Wednesday objected forcefully to Papadopoulos’ bid to avoid prison. “The defendant received what he bargained for, and holding him to it is not a hardship,” prosecutors on Mueller’s team wrote.

A year ago, Papadopoulos pleaded guilty to lying to the FBI in the course of Mueller’s probe. Recently, though, he changed legal teams and took a much more aggressive stand on his case.

Moss noted Sunday that two federal judges have already said Mueller’s probe is constitutional.

“Those opinions reject the notion that the Special Counsel is a principal officer for purposes of the Appointments Clause; they conclude that controlling D.C. Circuit and Supreme Court authority holds that the statutes relied upon to appoint the Special Counsel vested the Acting Attorney General with the necessary authority; and they hold that the Deputy Attorney General served as the Acting Attorney General—and thus the Department head—for purposes of making the appointment,” the judge wrote.

“Based on the reasoning contained in those opinions, the Court concludes that the prospect that the D.C. Circuit will reach a contrary conclusion is remote.”

Read Moss’ ruling below:

