Renna said staff voluntarily did the endorsement work outside office hours. But her testimony suggested a less-than-stark divide between campaign and government duties before an election in which Christie, eyeing a presidential bid, was trying to rack up bipartisan support.
The state's conflict-of-interest law and ethics codes specify that state time and resources cannot be used in pursuit of political activities.
At a recent news conference, Christie said "clear instructions were sent throughout the administration that if you wanted to volunteer time for our campaign or for any other campaign . . . that that had to be done during your free time."
"I think those lines were fairly clear," he said.
On Tuesday, lawmakers pressed Renna, former director of the intergovernmental affairs office (IGA), on how and when staffers pursued mayoral endorsements.
Renna, who described the office's function as "people helping people, state government helping local government," said endorsement-seeking was done on nights, weekends, or before work.
But several e-mails and issues discussed during the hearing suggested that the lines strayed into a gray area and that the office may have been used differently in past administrations.
In a June e-mail to Renna about an IGA staffer's meeting with Democratic Fort Lee Mayor Mark Sokolich, the staffer said the mayor talked about a development project and public safety issues. He also wrote that Sokolich "remains supportive of the administration and willing to help as needed, but there is a bleak outlook on any public endorsement."
Some have speculated the lane closures, which created gridlock in Fort Lee over four days in September, were meant as retaliation against Sokolich.
Renna said she did not know why the staffer included the line about endorsement in the meeting summary. "This is sort of an oddity I can't explain," she said.
If IGA employees sought endorsements from the mayors they assisted, "that conflation of official duties and campaign efforts is problematic," said Paula Franzese, a Seton Hall University School of Law professor who specializes in government ethics.
The concern is whether local officials believed they had to support Christie's reelection to win favorable treatment from the administration, Franzese said.
"The public trust is betrayed by the perception that official power would be wielded as a sort of quid pro quo in the attempt to secure support for the governor's reelection bid," she said.
According to an interview summary prepared by Gibson Dunn, the law firm Christie hired to review the lane closures, Renna told lawyers IGA staff members had received "mandatory directives" not to return phone calls quickly from certain mayors.
On Tuesday, Renna objected to the firm's use of "mandatory directives." She also denied the existence of a "hands-off mayors list" - a phrase another staff member used in a text message.
"The directive was never, 'Don't return this mayor's phone call,' " Renna said. "IGA conducted proactive outreach . . . that's what this meant. Let's pull back on the proactive outreach."
The summaries of the 75 interviews conducted by Gibson Dunn - which laid blame for the closures on Kelly and David Wildstein, a former official of the Port Authority of New York and New Jersey, while clearing Christie of wrongdoing - include several additional mentions of possible overlapping of government and campaign work.
Another IGA staffer told Gibson Dunn lawyers he remembered Kelly saying "that she had to check with 'Bridgewater' - meaning the campaign or [campaign manager Bill] Stepien - before approving certain things."
Stepien had served as deputy chief of staff for intergovernmental affairs before joining Christie's campaign in April 2013. He also ran Christie's 2009 campaign.
According to an e-mail provided to the committee by Renna, in January 2013, Stepien e-mailed Kelly and another IGA staffer, asking, "Have we started outreach to our Dem allies?"
Circulated in the e-mail chain was a list of Democratic mayors, along with Stepien's instructions that IGA staff could "play a role in the process if conversations occur after hours."
Insinuations of retribution against out-of-favor mayors and possible coordination with Christie's campaign differentiated IGA from the practices of past administrations, several former government staffers said.
Under Christie, the office "became a much more sophisticated and highly coordinated organization than it had been," said Carl Golden, a former spokesman for Republican Govs. Tom Kean and Christie Whitman, and now a senior contributing analyst at the William J. Hughes Center for Public Policy at Richard Stockton College.
Christie's staff seems to have been "overly aggressive, and probably indiscreet in what they did," Golden said.
Of the line between government duties and political activity - "always a moving target," Golden said - "you can nudge up against the line. But you can't obliterate it."
A former senior staffer in several Democratic administrations who works in state politics and spoke on the condition that his name not be used, said the IGA office had traditionally been staffed by former campaign workers with political backgrounds.
"It's the nature of the job. Mayors are also political," the staffer said.
But it was not past practice for office staff to also work on securing endorsements from mayors, the former staffer said.
"There's got to be a separation between those two functions," he said. "Not because you don't understand it, working in IGA, but because the mayors don't understand it."
Though the endorsement issue has drawn attention since the bridge scandal, "the fact that there's politics in the Governor's Office is not particularly shocking," said Ben Dworkin, director of the Rebovich Institute for New Jersey Politics at Rider University.
"Just because you're rewarding your friends and don't rush to help your enemies is not necessarily illegal," Dworkin said. But "it would appear that the closing of lanes may be the kind of thing that crosses a line."