New Jersey Governor Chris Christie was thrust deeper into a scandal with the release on Wednesday of emails showing his staff was involved in closing lanes at the George Washington Bridge, a move critics called political retribution.

Christie, a Republican widely expected to make a bid for the White House in 2016, has insisted he and his staff had nothing to do with the lane closings, which angered commuters and badly snarled traffic in the borough of Fort Lee at the New Jersey end of the bridge.

He has denied accusations that the shutdown was retribution against the Democratic mayor of Fort Lee, who did not endorse the governor’s re-election efforts. Rather, Christie and the Port Authority of New York and New Jersey have said the lane shutdowns were enacted for a traffic study.

The emails released on Wednesday promise to raise fresh questions about those accounts, showing that at least one of Christie’s top aides was involved in discussions about the lane closures weeks before the shutdown. The George Washington Bridge is among the world’s busiest, carrying some 300,000 vehicles on a typical day.

“Time for some traffic problems in Fort Lee,” the aide, Bridget Anne Kelly, wrote to a Port Authority executive in August.

The executive, David Wildstein, replied in an email: “Got it.”

The emails do not give a specific reason for the closings, which left commuters trapped in traffic jams lasting several hours.

In another message sent amid the gridlock, an unidentified author wrote: “Is it wrong that I’m smiling,” and Wildstein responded: “No.”

Christie canceled his only public event on Wednesday with no explanation, and a spokesman did not return a call seeking comment.

At a news conference in Trenton, New Jersey, Deputy Assembly Speaker John Wisniewski, a Democrat, said revelations about the emails showed “government at its worst.”

“Among other things, they call into serious question the honesty of this governor and his staff. As a result of what has been revealed today, this governor has a lot of explaining to do,” Wisniewski said.

Christie often touts his willingness to work with opponents as well as allies - a stance seen as a way of positioning himself as a national candidate able to close bitter partisan divides and win the White House.

A former prosecutor, Christie was highly visible working with Democratic U.S. Senator Cory Booker, the former mayor of Newark, and he notably praised President Barack Obama in 2012 for his response to New Jersey’s needs after Superstorm Sandy.

While Christie is popular, some think his blunt, tough-talking style may trip him up on the national stage.

He is known for engaging in shouting matches, hurling insults and waging belittling campaigns. Some opponents have reported being stripped of police security or being disinvited from political events after clashing with Christie.

In one not-untypical response, when asked earlier if he knew about the lane closings, Christie sarcastically replied that he personally had put out the traffic cones.

A spokesman for New Jersey’s Working Families Alliance said the emails reveal Christie was willing to sacrifice the interests of families and businesses who rely on the bridge.

“Now we have concrete proof that the Christie administration saw them all as collateral damage in a vindictive quest to punish its political enemies,” said the spokesman, Rob Duffey, in a statement.

Copies of the emails, many of them on private accounts, were obtained and published by the Bergen Record, The New York Times and other media.

The emails were supplied to the media by Wildstein, the Port Authority executive, in response to a subpoena issued by a panel of state lawmakers. A long-time Christie ally, Wildstein previously has admitted ordering the lane closures and resigned in December. He is due to testify before the panel on Thursday.

A second top Christie appointee at the Port Authority resigned a week later.

One email showed the Christie aide talking with Port Authority about ignoring Fort Lee Mayor Mark Sokolich, who was seeking an explanation for the unexpected closings.

“Radio silence,” Wildstein said in an email when asked if anyone had returned the mayor’s calls.

A text message to Wildstein attributed to the mayor read in part: “Someone needs to tell me that the recent traffic debacle was not punitive in nature…. Perhaps someone can enlighten me as to the errors of my ways.