A story that began with traffic cones at the George Washington Bridge in 2013 opened another chapter Tuesday as the highest court in the land took up the appeal brought by two former associates of Chris Christie of their convictions in what became known as the Bridgegate scandal.

Among the surprises Tuesday was the presence in the chambers of the United States Supreme Court of the former governor and his wife, as lawyers for Bridget Anne Kelly, his one-time aide, and ex-Port Authority official Bill Baroni, argued their clients were victims of an overreach by federal prosecutors seeking to criminalize what was political behavior.

That the Supreme Court took up their case amid the justices’ busy calendar came as a surprise to many, not the least of which was Kelly herself.

“I was overwhelmed and grateful when they agreed to do so back in June,” she said Tuesday. “And I am so honored to be here today.”

Kelly, the author of the infamous “Time for traffic problems in Fort Lee” email, and Baroni were convicted in late 2016 on multiple federal counts in connection with what prosecutors said was a scheme to punish Mayor Mark Sokolich, a Democrat, for failing to endorse Christie’s bid for re-election by engineering a massive traffic jam at the George Washington Bridge. Later, a federal appeals court upheld most of the counts.

Baroni had already begun serving his 18-month jail term and Bridget Anne Kelly, a mother of four, was gearing up for her 13-month sentence when the Supreme Court agreed to hear Kelly v. the United States.

Both the defense and prosecution had 30 minutes to present their case Tuesday morning, and both sides were questioned closely by an array of justices that spanned the political spectrum.

Yaakov M. Roth, Kelly’s attorney, maintained that the government was misusing a federal statute aimed at preventing property fraud by public officials.

“Once again, the government is trying to use the open-ended federal fraud statutes to enforce honest government at the state and local levels,” he said. “Its theory this time is that the defendants committed property fraud by reallocating two traffic lanes from one public road to another without disclosing their real political reason for doing so. This theory turns the integrity of every official action at every level of government into a potential federal fraud investigation.”

According to a preliminary transcript of the hearing, numerous justices pushed back hard. Sonia Sotomayor expressed pointed skepticism in her summary of Roth’s argument.

“I can see a headline that would say it’s OK for officials to use government public money in a way that is plainly unauthorized, not just in its motives but it’s in end use, and an official can and should not be — should never be liable for that. Our public officials now can use government resources … for their private ends,” she said.

In response, Roth sought to draw a distinction.

“I’m not trying to suggest that this is OK,” he said. “We don’t want public officials acting for personal reasons. We don’t want them acting necessarily for partisan or political reasons. But what I’m saying is the remedy for that is not the federal property fraud statutes.”

Roth said other avenues had been available to prosecutors.

“There may also be state law constraints on official abuses of authority. In fact, New Jersey has a statute called ‘Official Misconduct’ that is specifically directed toward unauthorized decisions with bad purposes,” he maintained.

For the government, attorney Eric J. Feigin, argued in part that Kelly and Baroni were rightly convicted because what they had done was not within their scope of authority.

“Their actions in this case were fraud in just the same way that it would be fraud for someone with no connection to the Port Authority to impersonate Port Authority supervisors and order Port Authority employees to realign Port Authority lanes,” he said, adding, “And they don’t get a free pass simply because their motive happened to be political.”

The justices were equally sharp in their questioning of Feigin and whether the government’s argument reflected a correct application of federal law.

“If I look at this, and I’m an ordinary juror, I’m thinking, you know, the object of this deception was not to obtain property,” said Justice Elena Kagan. “The object was to create a traffic jam. The object was to benefit people politically.”

Legal experts distilled the arguments.

“What the prosecutors argued is that these defendants used the lane changes as political retribution against the mayor of Fort Lee for not endorsing the governor. And they’re arguing that this is a misuse of public property and therefore a crime,” said Robert Mintz, a former prosecutor who’s now a partner at McCarter & English.

“What the defense has argued is essentially that, while this may be bad politics, while this may be corruption in a political sense, it’s not a crime, and really what the government has tried to do here is take bad politics and turn that into criminal activity,” he added.

Some observers saw the fact that the high court made the case one of the 150 it hears out of thousands of requests each year as a sign that the justices were trying to tighten the belt on federal prosecutors.

“The Supreme Court has been slowly ratcheting back the authority of federal prosecutors to turn these political corruption cases into criminal activity,” Mintz said. “And what they’re worried about is taking what is perhaps bad politics, routine politics in some states … and turn them into criminal activity. That’s where the Supreme Court seems to be troubled.”

In fact, Roth was the attorney for former Virginia Gov. Bob McDonnell whose corruption conviction was overturned by the justices, also on an argument of overreach by prosecutors.

Christie, who has said he was unaware of the traffic jam scheme and was never charged in the ensuing scandal, sat with his wife right in front of Kelly in the court chambers, after riding down to Washington on the same train as his former assistant. He did not speak to reporters.

The court is expected to hand down its ruling in the case in June.