WASHINGTON (Reuters) - A U.S. federal judge on Sunday denied a motion by George Papadopoulos, a former aide for Donald Trump’s 2016 presidential campaign, seeking to postpone his sentence pending a separate case he hoped would lead to his conviction being overturned.

Papadopoulos will report to jail on Monday to start his 14- day sentence after judge Randolph Moss dismissed his 11th hour bid to remain out on bail.

Papadopoulos, who pleaded guilty to lying to federal agents probing ties between the campaign and Russia, had sought to delay his sentence while a separate case challenging the legality of Special Counsel Robert Mueller’s appointment is ongoing. Moss said Papadopoulos’ motion lacked merit.

“The court, accordingly, concludes that Papadopoulos’ motion for a stay pending his appeal of this decision lacks merit,” Moss wrote in his ruling. “Plaintiff’s motion to continue bail and motion to stay his surrender date are hereby denied.”

Papadopoulos pleaded guilty in October 2017. In addition to the two-week jail term, Papadopoulos was sentenced to one year of supervised release, 200 hours of community service and a $9,500 fine.

At sentencing in September he told the judge that he had made a “dreadful mistake” and that he hoped to redeem himself. But he soon started attacking the Mueller probe on Twitter and in media appearances, describing the investigation as unjust and politically charged.

In seeking an extension of his bail, Papadopoulos had argued that his appeal against Mueller’s appointment raised “a substantial question” and that it would be unjust to require that he serve his sentence before a ruling on this matter. But Moss cast doubts on the success of the appeal.

“He has failed to demonstrate that the D.C. Circuit is likely to conclude that the appointment of the Special Counsel was unlawful and, indeed, he has failed even to show that the appeal raises a ‘close question’ that ‘very well could be decided’ against the Special Counsel,” said Moss.