NEWARK--Jurors in the Bridgegate trial were unexpectedly dismissed for the day early Wednesday afternoon, as prosecutors and defense attorneys wrestled for hours over an unspecified "legal issue" that none would discuss.

Both sides in the high-profile political trial could be seen going in and out of the courtroom all day, but nothing was placed on the record and no one else was allowed inside.

Earlier in the day, defense attorneys asked the judge to reconsider her instructions to the jury on Tuesday, which they argued could "eviscerate" their case. It was the only motion filed in the case Wednesday.

At issue was a note from the jury asking whether Bridget Anne Kelly and Bill Baroni, the two former Christie administration insiders charged with illegally shutting down toll lanes at the George Washington Bridge to cause traffic problems in Fort Lee, could be found guilty of conspiracy if their intent had not been to punish Fort Lee Mayor Mark Sokolich, as prosecutors have alleged.

U.S. District Judge Susan Wigenton on Tuesday had ruled that motive was not an issue in the case, and told the jury the answer to their question was "yes."

Michael Critchley, who represents Kelly, argued that the judge's response would "direct a verdict of guilty."

Baroni, the former deputy executive director of the Port Authority, and Kelly, who served as a deputy chief of staff to the governor, are charged with conspiracy and fraud in connection with the 2013 lane closures at the George Washington Bridge that caused traffic havoc in Fort Lee, in apparent retribution targeting Sokolich over his refusal to endorse Gov. Chris Christie.

In his filing on Wednesday, Critchley asked the judge to reconsider. He said she should have either told the jury "no," or that while a defendant could be convicted without intending to punish the mayor, there first had to be a finding that Baroni and Kelly had "intentionally misapplied the property of the Port Authority in some other illegal manner," rather than believing the realignment of the toll lanes was a legitimate traffic study.

He said the indictment charged a conspiracy to accomplish a specific unlawful purpose--in this case political retribution against the Fort Lee mayor. The attorney said the government must prove that unlawful purpose.

"While it is true that motive is not an essential element of every conspiracy, it is an essential element when the grand jury charges a defendant with conspiring to do so, and in fact, doing something he is authorized to do, but doing it for an improper purpose," Critchley wrote.

He said it was an error to instruct the jury otherwise, and that the court should correct that error now, asking the judge to re-instruct the jury.

On Tuesday, Critchley, who represents Kelly, argued strongly against the judge's original response.

The judge has yet to rule on the motion.

Whether that was what sparked the early jury dismissal, or of there were other issues, still remains unknown. But federal prosecutors and defense attorneys spent the day moving in and out of the courtroom, without saying anything.

Attorneys for Kelly and Baroni have both maintained that the two were duped by key prosecution witness David Wildstein, who orchestrated the toll lane shutdowns at the George Washington Bridge in September 2013 in a scheme of political retribution targeting Sokolich for his refusal to endorse the governor.

Kelly and Baroni both testified that they believed Wildstein's cover story that the lane shutdowns were part of a legitimate traffic study at the toll plaza.

The defense has argued that if the defendants believed the lane closures were part of a traffic study, or acted through an honest misunderstanding, then they had simply acted in good faith and had to be found innocent on all charges.

Matt Arco may be reached at marco@njadvancemedia.com. Follow him on Twitter @MatthewArco or on Facebook. Follow NJ.com Politics on Facebook.

Ted Sherman may be reached at tsherman@njadvancemedia.com. Follow him on Twitter @TedShermanSL. Facebook: @TedSherman.reporter.