“The evidence may show that others could have, should have, perhaps known certain aspects of what was going on in Fort Lee,” he said. “Perhaps you will even wonder what happened to those people. But at the end of this case the only issue for you to decide is whether Bridget Kelly and Bill Baroni are guilty of the crimes with which they are charged beyond a reasonable doubt. That’s it.”

Image Gov. Chris Christie Credit... Mel Evans/Associated Press

Defense lawyers quickly seized on his comments in their own opening statements.

Michael Critchley, a lawyer for Ms. Kelly, a former deputy chief of staff to Mr. Christie, said: “We know who they’re talking about. They’re talking about Governor Christie. They’re talking about Kevin O’Dowd.” (Mr. O’Dowd was the governor’s chief of staff at the time of the closings.)

A spokesman for Mr. Christie, Brian Murray, responding to the prosecutor’s assertion, referred reporters on Monday to statements the governor made in 2014, in which he said he had not known about the plan to close the lanes. Mr. Murray declined to address whether the governor knew about the closings while they were happening.

The office of the United States attorney, Paul J. Fishman, declined to comment on why the governor was not charged, but Mr. Fishman has said in the past that merely knowing is not a federal crime.

Mr. Christie was intimately woven into the story both sides told in the packed courtroom on Monday.

Prosecutors and defense lawyers alike described an administration tightly controlled by the governor, one that worked hand-in-hand with his re-election campaign to trade favors for endorsements. The governor was trying to win a big and broad margin of victory, and to win over Democratic mayors like Mr. Sokolich, so he could make the case that he was the Republican best able to win the White House.

Mr. Khanna said Mr. Baroni covered up the lane closings because “this was something that was important to Trenton.”

He added, “Trenton: the governor’s office.”

Mr. Baroni’s lawyer, Michael Baldassare, later told the jury it would be hearing a lot about Trenton. “Trenton, Trenton, Trenton; Trenton is the governor,” he said. “Let’s make no mistake. Open a dictionary: Trenton, the governor.”