The Republican presidential candidate Chris Christie came out swinging on Sunday, in response to the latest developments in the so-called Bridgegate scandal.

The New Jersey governor, known for his abrasive political style, said on NBC the media should “stop blathering” about Bridgegate and insisted what mattered was how he reacted to it, and said it had not left “a stain on my administration”.

He also sought to deflect such critical press attention to the Democratic presidential frontrunner, Hillary Clinton.

Bridgegate concerns the September 2013 closure of traffic lanes on the busy George Washington bridge, which runs between Fort Lee, New Jersey, and upper Manhattan, in an alleged act of political payback.

As successive investigations have been carried out, allies of the governor, including members of his staff have been indicted. Christie himself has denied knowledge of any plan to close the lanes, and no evidence has come to light indicating any culpability on his part.

This week the CEO of United Airlines, Jeff Smisek, resigned as a result of a subsequent investigation into the workings of the Port Authority, the body responsible for the bridge, which is run jointly by New York and New Jersey.

Investigators are focusing on conversations United management had with the chairman of the Port Authority board of commissioners, David Samson, a Christie appointee and friend, over supposed “quid pro quo” political dealings.

The scandal has not helped with Christie’s poll ratings – an average of 2.5% support in the 16-strong Republican field being only just enough to get him on to the main stage for this week’s second debate.

“You have absolutely no idea as you sit here today that he did anything wrong,” Christie told NBC host Chuck Todd on Sunday, when asked about David Samson. “Nor does anyone else. So let’s just stop reading the newspapers, OK, and just blathering back what that is.

“Here’s the bottom line. When you have all these folks working for you, David included, the fact is you hold them to high standards and if they don’t meet those high standards, what a decisive leader does is take action and to terminate them.”

Christie sought to focus attention instead on Hillary Clinton, who is under pressure over her use of a private email server while US secretary of state, in a scandal which has not yet acquired the dreaded “gate” suffix.

“What really matters, as Hillary Clinton is finding out, is how you react to a crisis,” Christie said. “Not that there ever will be any crisis … what did I do? When we had a crisis the next day I went out and took questions for an hour and 15 minutes, no holds barred.

“Let’s wait and see if Mrs Clinton ever does one fifth of that on her crisis.”

Christie said that as a presidential candidate he could offer “honesty and candor, not perfection” and added that nor could he offer perfection from everybody employed under him. He also pointed to three investigations into Bridgegate that he said had not contradicted anything he has said on the issue.

“It’s about how a leader reacts,” he said, “and I wish maybe Barack Obama had reacted that way to the IRS scandal [over allegedly punitive treatment of conservative groups by the Internal Revenue Service, an affair in which the president fired the acting IRS commissioner] … and been transparent.”

Christie continued: “And maybe he should stand up today and say to Hillary Clinton: ‘Madam Secretary, this is a stain on my administration, stand up and fully cooperate, reveal all the answers to every question and ask all the people that were around you to cooperate as well.’

“He hasn’t done that,” Christie concluded, “and that’s a failure of leadership”.

Asked by Todd if the Port Authority was a stain on his administration, Christie said: “No, it’s not. Nothing has been proven there. Let’s see what happens, Chuck.”