A former foreign policy adviser on the Trump presidential campaign who lied to authorities in the special counsel's Russia investigation must surrender Monday to begin a 14-day prison term, a Washington federal judge ruled Sunday.

George Papadopoulos, who was sentenced in September, had urged the court to delay the start of his prison sentence pending the outcome of a challenge to the power of the special counsel, Robert Mueller III, in the U.S. Court of Appeals for the D.C. Circuit.

The appeals court heard arguments this month from a grand jury witness who contends the appointment of Mueller was unlawful. Lawyers for Papadopoulos had argued that any ruling against Mueller would undermine the prosecution and conviction of the false statements charge.

Two trial judges—Chief Judge Beryl Howell and Judge Dabney Friedrich—have concluded separately that Mueller was lawfully appointed, U.S. District Judge Randolph Moss noted in his ruling Sunday.

“Chief Judge Howell and Judge Friedrich have both issued thorough and carefully reasoned opinions rejecting the arguments that Papadopoulos now champions,” Moss wrote. Papadopoulos, the judge said, failed to show how a ruling from the D.C. Circuit against Mueller would “likely” overturn Papadopoulos's conviction.

Papadopoulos, at the time of his sentencing, appeared contrite, and Moss pointed to the remorse when he ordered the 14-day prison term. Papadopoulos had faced up to six months in prison.

In the weeks since his sentencing, Papadopoulos has shown a change of heart, speaking out publicly against Mueller and hiring a new team of lawyers to challenge his conviction.

Prosecutors last week urged Moss not to delay the start of the prison term. “Here, as part of a favorable plea agreement, the defendant waived his appeal and did not file a timely notice. The defendant received what he bargained for, and holding him to it is not a hardship,” prosecutors said.

Moss said Papadopoulos has only himself to blame for the last-minute push to delay the start of his prison term.

The judge said “Papadopoulos has not identified any extenuating circumstances—nor is the court aware of any—that would overcome the presumption against granting such an eleventh-hour stay.”

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