The US Supreme Court has overturned the convictions of two state officials who were jailed for their role in the Bridgegate political revenge plot.
The aides to then-New Jersey Governor Chris Christie had arranged a bridge traffic jam to target a mayor who did not endorse Mr Christie's re-election.
But the court unanimously ruled that, as the scheme did not aim to obtain money or property, it was not fraud.
The traffic scandal helped derail Mr Christie's 2016 presidential campaign.
Former aide Bridget Anne Kelly and former Port Authority of New York and New Jersey deputy executive director Bill Baroni were convicted on nine counts of conspiracy and fraud in 2016.
Prosecutors said the 2013 plan to shut down the George Washington Bridge was a way of exacting revenge on a local mayor who refused to back Mr Christie in his re-election bid.
The unannounced closures to 12 toll lanes on the bridge - an entry point to Manhattan - caused a monumental traffic jam for four days. Only one lane was available to commuters.
Justice Elena Kagan, who wrote the court's opinion, said that the aides "jeapordised the safety of the town's residents" but "not every corrupt act by state or local officials is a federal crime".
Both officials had testified in court that the governor had known about the lane closures on the country's busiest bridge in advance.
Mr Christie has said he had no prior knowledge of their plan and was never charged.
Lawyers for Ms Kelly had said the plot was for a political motive, not fraud, and that prosecutors had overreached in their charges.
Ms Kelly did not serve her 13-month sentence, as she appealed to the Supreme Court last year.
Mr Baroni had begun serving his 18-month prison term but was released when the top court took up the appeal.
What's the reaction?
Mr Christie called the decision a "complete exoneration" for his team, criticising Obama-era justice officials for prosecutorial misconduct.
"As many contended from the beginning, and as the Court confirmed today, no federal crimes were ever committed in this matter by anyone in my administration," he said, adding that "justice has finally been done".
Mr Christie said prosecutors were "in search of a predetermined and biased outcome" and had "violated the oath sworn by every member of the Department of Justice".
Ms Kelly said in a statement to Reuters: "While this may finally have made this case right for me, it does not absolve those who should have truly been held accountable."
A lawyer for Mr Baroni said his client was "heartened that the system ultimately worked", Reuters reported.
What did the Supreme Court say?
The court noted that the government had charged Ms Kelly and Mr Baroni under federal statutes against wire fraud and fraud on federally funded programmes - both of which target schemes to obtain money or property.
"The evidence the jury heard no doubt shows wrongdoing- deception, corruption, abuse of power," Justice Kagan wrote, adding that the fraud laws "do not criminalise all such conduct".
"The realignment of the toll lanes was an exercise of regulatory power - something this Court has already held fails to meet the statutes' property requirement.
"And the employees' labour was just the incidental cost of that regulation, rather than itself an object of the officials' scheme. We therefore reverse the convictions."