But now, a key theory of that statute could be gutted because of a challenge by two defendants in another well-known case — “Bridgegate,” the September 2013 closing of access lanes to the George Washington Bridge, which connects Manhattan and New Jersey, to punish a mayor for refusing to offer a campaign endorsement.

The U.S. Supreme Court, in a decision that surprised legal experts, agreed last week to hear an appeal of the defendants’ corruption convictions in a move that could significantly weaken the ability of prosecutors to go after what they determine to be political malfeasance.

The court’s decision to take on the appeal by the defendants, Bridget Anne Kelly and Bill Baroni, suggests that the justices are open to overturning their convictions, legal experts said, and follows other rulings that have chipped away at federal corruption laws.

“There has been this stream of cases coming from the Supreme Court that has continued to limit prosecutorial discretion and prosecutorial authority when it comes to corruption cases,” said Jessica Tillipman, an assistant dean at the George Washington University Law School. “So the fact that they took on another corruption case to me signals that there’s a good chance that the statutes will be further narrowed once again.”

The bridge scheme drew national attention and undermined the presidential ambitions of the then-New Jersey Gov. Chris Christie. Kelly and Baroni, top aides to Christie, were charged with orchestrating the closing of the lanes leading to the bridge.

At issue in the case is a fraud theory used to prosecute under the mail and wire fraud statutes known as a “right to control.” It rests on the idea that the owner of an asset is defrauded when somebody uses that asset and lies about what they are using it for. In the college admissions scandal, for example, prosecutors said offers of acceptance were misused.

The court has already significantly raised the bar when it comes to prosecuting politicians, and what was once viewed as illegal is being increasingly regarded as normal political behavior, legal experts said.

One of the most significant decisions came in 2016, when the Supreme Court overturned the corruption conviction of former Gov. Bob McDonnell of Virginia, who had been accused of accepting luxury items, loans and vacations in exchange for helping a local businessman.

In its unanimous ruling, the court said the gifts were permissible because in setting up meetings and making introductions for the businessman, McDonnell had not betrayed his office or, as the law says, taken an “official act.” To prove corruption, the court said there had to be a clear official government decision or act, essentially creating a more stringent definition of the law.

The McDonnell decision upended several high-profile federal prosecutions, including cases involving Sheldon Silver, the once powerful speaker of the New York Assembly, Dean G. Skelos, the former majority leader of the New York Senate, and Sen. Robert Menendez of New Jersey. All three had already been indicted at the time of the decision.

A federal appeals court overturned the convictions of Silver and Skelos. Still, appellate judges made clear that sufficient evidence existed to prove the men had acted corruptly.

Silver and Skelos were found guilty at new trials after juries were presented a more narrow definition of what constituted corrupt behavior.

In Menendez’s case, a judge declared a mistrial after jurors could not reach a verdict on charges that the senator had provided favors to a wealthy donor in exchange for lavish gifts.

Federal prosecutors abandoned efforts to try Menendez after the judge threw out several counts of the charges, saying that the prosecution had not proved a quid pro quo under the definition laid out by the McDonnell decision.

The appeal in the Bridgegate case is now testing another aspect of federal corruption law.

“What’s always marked this case from being a little different than standard corruption cases was that this wasn’t about personal gain, or at least personal gain in a monetary sense,” said Daniel C. Richman, a professor at Columbia Law School and a former federal prosecutor. “If money isn’t nakedly involved, you end up having more complex and contestable liability theories.”

The defense team for Kelly and Baroni argued that even if they did hatch a scheme to block the access lanes, which they have denied, it would not constitute a crime because there was no personal financial or material gain, and the agency that operates the bridge, the Port Authority of New York and New Jersey, was never defrauded.

In the end, the defense lawyers argued, the affair was nothing more than the rough and tumble of political gamesmanship, likening it to a mayor directing his public works department to plow the streets of his political opponents last during a snowstorm.

Zephyr Teachout, a law professor at Fordham University and a former candidate for New York attorney general, said it is likely the defense will argue that Bridgegate was just politics. “And this court has been extremely sympathetic to that kind of argument,” she said.

The hearing before the Supreme Court, likely in December or January, will prolong a political saga that has plagued Christie and his allies for more than five years.

Sparked by the now infamous “Time for some traffic problems in Fort Lee” email sent by Kelly, the scandal engulfed the Christie administration, leading to indictments for Baroni and Kelly in 2015, and their conviction in November 2016.

While the Christie administration said the lane closings were ostensibly part of a traffic study, an investigation revealed that they were political retribution against the mayor of Fort Lee, a town at the foot of the George Washington Bridge, for not endorsing Christie’s reelection. Christie has denied any knowledge or involvement in the scheme.

The closings led to days of massive traffic jams near the world’s busiest bridge.

Both Kelly and Baroni appealed their convictions and were able to get part of their sentences reduced. In February, Baroni was sentenced to 18 months in prison. He reported to a federal corrections facility in Pennsylvania in April. Kelly was sentenced to 13 months and was to report to prison later this summer, in what many thought would be the final chapter in the protracted scandal.

Now, following the Supreme Court’s decision to take up the case, Baroni has been released from prison on bail and Kelly will not have to report to prison until the Supreme Court renders its decision.

Michael Critchley, a lawyer for Kelly, has steadfastly maintained that federal prosecutors stretched the boundaries of the law to make a case against his client.

“We’ve always said this was an indictment in search of a crime,” he said. “You may question political motives, but the Supreme Court will say are political motives enough for holding someone criminally liable for an offense?”

The U.S. solicitor general’s office had recommended that the Supreme Court not take up the case, pointing to the “approximately $1,828.80 for the labor necessary to carry out the phony traffic study” as evidence that the Port Authority was indeed defrauded of resources.

The solicitor general’s office also took exception to the mayor and snow plow analogy.

“Those examples, in contrast to the facts of her case, involve officials who possess unilateral authority over discretionary resources, therefore do not need to lie to allocate those resources,” the solicitor general’s office wrote.

But now that the court has agreed to hear arguments, some legal experts say the case could again reframe what is acceptable political conduct.

“One does wonder, implicitly, how the Supreme Court got to this extraordinarily cynical view of politics and public service where this dodgy behavior is just part and parcel of the political game,” said Dan Weiner, a senior counsel at the Brennan Center for Justice. “I would like to see the courts grapple more earnestly with the thinking that, whether these decisions are correct or not, allowing conduct like this to go unsanctioned and any suggestion that this is just politics is just corrosive. And that has done a lot of damage.”

This article originally appeared in The New York Times.