A three-judge federal appeals court panel on Friday unanimously affirmed the public corruption convictions against former Virginia governor Robert F. McDonnell, thoroughly rejecting each argument from the onetime Republican rising star and declaring that it had “no cause to undo what has been done.”

The 89-page opinion from the U.S. Circuit Court of Appeals for the 4th Circuit brings to a close an important chapter in the story that emerged more than two years ago when The Washington Post first reported on the governor’s strange relationship with a Richmond businessman. It also means that the first Virginia governor to be convicted of a crime will probably have to go to prison in the coming months.

Experts say it could energize federal prosecutors across the country and put public officials on notice that almost anything they do on behalf of a benefactor can be construed as the illegal end of a corrupt bargain.

“I think it is precedent-setting,” said Barry Pollack, a white-collar criminal defense lawyer at the Miller & Chevalier law firm who is unaffiliated with the case.

List of gifts given to the McDonnell family from Jonnie Williams.

McDonnell and his wife, Maureen, were convicted in September after a gripping trial in which the former governor’s financial woes and marital troubles were aired publicly. Prosecutors paraded before jurors example after example of the luxurious life the McDonnells were able to lead when Richmond businessman Jonnie R. Williams Sr. paid the tab — a life that included expensive vacations, a Ferrari ride, a Rolex watch and $120,000 in sweetheart loans. Jurors, in turn, convicted the McDonnells of helping Williams promote his business as part of a corrupt quid pro quo exchange.

McDonnell, 61, was ultimately sentenced to two years in prison; his wife was sentenced to a year and a day.

Although the appeals court’s decision is a major blow to McDonnell’s chances of exoneration, the case is far from over. Maureen McDonnell is still pressing her own appeal, and Friday’s ruling did not explicitly affect her. Her attorney declined to comment.

The former governor, too, has myriad options left to pursue. His attorneys have 14 days to ask the same three-judge panel — or the entire 4th Circuit Court of Appeals — to hear the case again. After — or instead of — that, they could go to the Supreme Court.

McDonnell said in a statement that he was “greatly disappointed” with the court’s decision but remained optimistic that he would ultimately be cleared.

“During my nearly 40 years of public service, I have never violated my oath of office nor disregarded the law,” McDonnell said. “I remain highly confident in the justice system and the grace of our God that full vindication will come in time. I remain very blessed to have the unwavering support of my family and great friends which continues to sustain me.”

McDonnell’s attorneys asserted: “The fight for justice for our client is far from over.”

Former Virginia governor Robert F. McDonnell has been sentenced to two years in prison. Here’s a look at the corruption case against McDonnell, by the numbers. (Julie Percha/The Washington Post)

When — and how — the former governor will have to report to prison remained murky Friday, although experts said he would likely have to do so in the coming months. The 4th Circuit had allowed McDonnell to remain free while his appeal was pending. Experts said that U.S. District Judge James R. Spencer would probably undo that decision but act only after the court issues its formal mandate in the case, which could come in three weeks or more if McDonnell asks for another hearing.

Experts said Spencer would probably give McDonnell a date by which to report and the federal Bureau of Prisons would try to find an appropriate facility for him. William Jefferson, a former member of the U.S. House who was also convicted in a public corruption case, was ordered to report to prison about a month after he lost his appeal, although he took his case from there straight to the Supreme Court.

McDonnell’s appeal hinged largely on the argument that he neither performed nor promised to perform any “official acts” for Williams — a point prosecutors were required to prove. He also argued that the definition jurors were given for the term “official act” was so broad that it would criminalize routine political dealings.

Williams, indeed, got little of what he wanted. He received no state studies of his dietary supplement, Anatabloc, and no other type of state funding. He was also unable to add his supplement to the state’s health plan.

The appeals court judges, though, rejected McDonnell on every front. The opinion — written by judge Stephanie D. Thacker, who was appointed by President Obama, and joined by Robert B. King and Diana Gribbon Motz, who were appointed by President Bill Clinton — asserted that the government had “exceeded its burden” in the case. Thacker wrote that jurors were instructed appropriately and that McDonnell’s actions for Williams were official, no matter how inconsequential the former governor thought they were.

“Appellant argues that these actions — asking a staffer to attend a briefing, questioning a university researcher at a product launch, and directing a policy advisor to ‘see’ him about an issue — are too insignificant to constitute official acts,” Thacker wrote. “We disagree.”

Thacker cited three particular ways in which McDonnell tried to use his office to help Williams: trying to get researchers to study Anatabloc; trying to get the state tobacco commission to fund studies of an ingredient in Anatabloc; and trying to get Anatabloc included in the health insurance plan for state employees. Such acts were undeniably official, she wrote.

“These were all government matters, and Appellant, as head of the Commonwealth’s government, was in a prime position to affect their disposition,” Thacker wrote.

Experts said overturning the ruling will not be easy. Jacob Frenkel, a white-collar criminal defense lawyer, said that the judges’ decision was an “emphatic endorsement” of how the case was tried and that it might affect other public corruption cases.

“A resounding decision like this will energize prosecutors and cause defense lawyers to think far more aggressively about whether to accept plea terms,” Frenkel said.

U.S. Attorney Dana Boente, whose prosecutors in the Eastern District of Virginia handled the case, said in a brief statement that he was “pleased” with the ruling.

Pollack, the lawyer from Miller & Chevalier, said the decision was “good news, bad news” for other public officials who might walk the line of corruption. The good news: “There has to be an expectation that the official is going to undertake a specific official act in return for the benefit he is receiving,” Pollack said. The bad: “Almost anything is an official act.”

Brian Whisler, an attorney with Baker & McKenzie who represented state employees in the case, said the decision “does serve notice that it doesn’t take much, and that public officials need to be aware of who they’re dealing with very conscientiously.”

Thacker also rejected each of McDonnell’s less-significant arguments, including that jurors were not questioned thoroughly enough about pretrial publicity and that the governor should have been given a trial separate from his wife.

“Appellant received a fair trial,” she wrote, “and was duly convicted by a jury of his fellow Virginians.”

Rosalind S. Helderman contributed to this report.