Former New York City Mayor Rudy Giuliani said New Jersey Gov. Chris Christie's explanation was "pretty darn credible" that he didn't know about a plan to create traffic jams near the George Washington Bridge last year in what critics say was an act of political revenge.

Christie, who was significantly ahead in his race for a second term, said he didn't know his deputy chief of staff gave the go-ahead to close two lanes to the bridge in September, backing up traffic for hours in Fort Lee.

Giuliani said his friend and fellow Republican Christie likely was distracted by his campaign and didn't realize what his aide was doing.

"During campaign mode, you miss a lot of things. You're not paying as much attention," Giuliani told ABC "This Week" Sunday. With "every administration, every president, every mayor, every governor, something goes wrong below them, and then the press asks, gosh, how do they not know, how do they not realize?"

"He said he didn't know. I think it's pretty darn credible. He wouldn't make this blanket denial unless it's not true."

Democrats say the artificially created traffic jams were political retribution against the Democratic mayor of Fort Lee, who didn't support Christie's re-election bid.

Christie fired his political adviser Bill Stepien, a former Giuliani staffer, and three others over the scandal.

Giuliani said doesn't think the scandal will be career-ending for Christie, who has been mentioned as a possible GOP presidential candidate in 2016.

"He's handled it the best way you can possibly handle it," said Giuliani, a 2008 Republican president candidate. "He's held a press conference. He's flatly denied it.

"I'm pretty sure that this is going to go away. Obviously, it can take a while. There are going to be more iniquities … but I don't think it's going to be fatal."