Former Virginia governor Robert F. McDonnell pauses as he addresses reporters after his sentencing hearing in Richmond on Jan. 6. (Jay Westcott/Reuters)

Former Virginia governor Robert F. McDonnell will avoid prison while the U.S. Supreme Court considers whether to review his conviction on corruption charges, the justices decided Monday.

The one-paragraph order was a dramatic — perhaps unprecedented — reprieve for the Republican former governor, who lost a lower-court appeal and who would have had to begin serving a two-year prison sentence without the Supreme Court’s intervention.

As is customary in granting a stay, the court did not explain its reasoning; none of the justices signaled disagreement.

But the action greatly increases the chances that the court will consider McDonnell’s argument that he did not cross the line from doing routine political favors for a constituent and friend to corruptly using the power of his office to aid a man who befriended the McDonnell family.

McDonnell and his wife, Maureen, were convicted nearly a year ago of public corruption for lending the prestige of the governor’s office to Richmond businessman Jonnie R. Williams Sr. in exchange for $177,000 in loans, vacations and luxury goods. The former governor was sentenced to two years in prison; Maureen McDonnell received a year and a day.

Both, though, were allowed out on bond with their appeals pending. The former governor’s conviction was upheld by a unanimous panel of the U.S. Court of Appeals for the 4th Circuit, and that court said he could not stay out of prison while asking the Supreme Court to hear his case.

McDonnell said in a statement: “I am grateful for the Supreme Court decision today and thank Almighty God for His protection and provision for me and my family.”

McDonnell’s attorneys argued that Virginia’s 71st governor “may well complete his 2-year prison sentence” before the justices rendered a decision on his petition to have the conviction overturned. It would be wrong, they said, if he were to later “have the critical legal premise for the conviction invalidated, or the fundamental unfairness of the trial confirmed.”

“A 24-month sentence is a 24-month sentence, whether it begins in August 2015 or March 2016,” they told the court.

A stay request requires the court to find a “reasonable probability” that it will accept the case and a “fair prospect” that a majority would overturn the lower court’s decision.

When the court considers McDonnell’s petition later this year, it would require the consent of four of the nine justices to schedule the case for a full briefing and oral arguments. There is time for them to accept and decide the case in the court term that will begin in October.

McDonnell assembled a powerful coalition of people to protest his conviction, including former officials of Democratic and Republican presidential administrations, former prosecutors and a bipartisan group of 44 former state attorneys general.

The former governor’s case presented the justices with a chance to define the line “separating lawful politics from criminal corruption,” his attorneys said.

Hank Asbill, an attorney for McDonnell, said, “We’re obviously very pleased with the decision, and we look forward to a full merits briefing.”

U.S. Solicitor General Donald B. Verrilli Jr., representing the federal government, had told the court that McDonnell’s conviction did not merit the court’s review. Although the government agreed that McDonnell was not a flight risk, Verrilli said there was no reason to delay the former governor’s imprisonment.

Verrilli told the court that the government could not find one instance in which the justices had allowed someone to remain free after an appeals court had upheld his conviction.

McDonnell’s application said his case presented two issues worth the court’s time: whether the conduct for which he was convicted was actually illegal and whether the lower-court judge had made sure he was tried by an impartial jury.

McDonnell said he was convicted for benign gestures such as arranging meetings or attending public events with Williams. He called it a “political prosecution” and the “first time in the history of the nation that an official has been convicted of corruption despite never putting an official thumb on the scales of any actual government decision.”

But Verrilli’s response noted the appeals court’s finding that the government exceeded its burden by proving that McDonnell “did, in fact, use the power of his office to influence governmental decisions” on the issues important to Williams.

“When a sitting state governor secretly receives payments totaling more than $177,000 over two years, in exchange for agreeing to help the payor obtain valuable benefits through the governor’s influence over other state officials, his conduct readily falls outside” the kinds of favors public officials routinely perform, Verrilli argued.

McDonnell’s claim did not raise the broad questions of law that is the stuff of Supreme Court review, the government argued. Instead, the government said, his conviction represented a correct “application of settled legal principles to the facts established at trial.”

In July, a unanimous panel of the appeals court in Richmond upheld McDonnell’s conviction, and the full court declined to review the panel’s decision. Eight of the court’s judges said that McDonnell should begin serving his sentence while asking the Supreme Court for a review. The seven other judges on the court recused themselves from considering the request of the politically connected McDonnell.

The appeals court will consider Maureen McDonnell’s appeal in October.

Without the Supreme Court’s order, McDonnell’s case would have been sent back to U.S. District Judge James R. Spencer, who would have selected a date by which the former governor was to report to prison. Federal officials would then have picked a facility appropriate for him, taking into account available bed space, his particular security risks and other factors.

McDonnell had requested to remain near his home in the Richmond area, possibly at the Federal Correctional Institution Petersburg Low.