The support from former New York City Mayor Rudy Giuliani, Louisiana Gov. Bobby Jindal and Wisconsin U.S. Rep. Paul Ryan put Republicans on the offensive and the Democratic chairman of a state legislative committee investigating the September lane closures near the George Washington Bridge on the defensive the day Christie's state hosts the Super Bowl.
Also Sunday, a member of Christie's administration who was subpoenaed by lawmakers investigating the lane closings confirmed she had resigned. Christina Genovese Renna left the governor's office Friday, according to her lawyer. Renna had reported to ousted Deputy Chief of Staff Bridget Kelly, who apparently set the lane closings in motion with an email saying "time to cause some traffic problems in Fort Lee."
Christie, a potential 2016 presidential contender, has been going about Super Bowl ceremonial duties and has not taken questions about the scandal in recent days. He didn't respond Saturday when some spectators booed him at an appearance in New York City's Times Square. He planned to watch Sunday's game with his family from a luxury box at MetLife Stadium.
Giuliani, appearing on CBS' "Face the Nation" took aim at the credibility of two figures central to the scandal: John Wisniewski, who's leading the investigative probe, and David Wildstein, the former Christie loyalist who as an executive at the Port Authority of New York and New Jersey last year ordered the lane closures after receiving Kelly's email, as someone with less than pure motives.
He said Wildstein "wants somebody else to pay his legal bills and he can't get them paid unless the governor is responsible."
The unannounced lane closures caused massive gridlock in Fort Lee in September, delaying emergency vehicles and school buses and tying up some commuters for hours over four mornings. New Jersey legislators are investigating whether Christie aides engineered the lane closures to send a message to the town's Democratic mayor. The U.S. Attorney's office is also investigating.
On Friday, Wildstein's lawyer wrote a letter to the Port Authority saying evidence exists that Christie knew about the traffic jams in Fort Lee as they happened. He did not disclose any evidence in the letter.
Giuliani said Wisniewski, a Democratic assemblyman, is prejudiced and has ulterior motivations as a "guy who'd like to be governor."
Wisniewski also appeared on "Face the Nation" and defended his role and his previously stated doubts about what Christie knew and when.
"What I've said is I have skepticism about the governor's statement," he said. "I haven't said that the governor has responsibility for this. I haven't said that the governor knew when this was happening."
Democrats have taken to other forums to bash the governor. The Democratic National Committee started posted an online ad Sunday comparing Christie to a football player who seemed unstoppable before the scandal. "It's going to be a long game," the ad says.
By Saturday, Christie's allies were striking back after Wildstein's claim. The governor's team sent an email to politically plugged-in allies who might be in a position to defend Christie, bashing Wildstein and his accusations.
The message to donors, journalists and voters: Christie was not ceding ground.
And the supporters picked up those themes.
Ryan, appearing on ABC's "This Week," described Wildstein's allegations as "one person's word against the other" and said, "Nothing has been proven and you always give a person the benefit of the doubt in those kinds of situations."
Jindal, last year's RGA chairman, said Democrats who have called for Christie to step down from the RGA don't understand the organization or the role of its chairman. "The reality is within RGA, no one governor is more important than the other," he said.
The statement Sunday from Renna's lawyer, Henry Klingeman, said she said been considering leaving since after the November election, which Christie won decisively. She said the transition to a second term is a "natural time" to pursue opportunities in the private sector.
"I have spent almost four years working hard for a governor I continue to respect and admire," she said in the statement.
Renna is among 17 people close to Christie subpoenaed by a legislative panel, almost all of whom have asked for extensions from Monday's deadline. She is the fifth person close to Christie to lose their job amid the scandal. The others have been fired or resigned.
Christie's spokesman declined to comment on the resignation.
Mulvihill reported from Haddonfield.