David Samson, chairman of the Port Authority and ally of New Jersey Gov. Chris Christie, tendered his resignation on Friday — not because of his involvement in the bridge scandal, Christie assured the press, but because he was old and tired.

Christie held the press conference largely to field questions about the report issued by Gibson, Dunn & Crutcher LLP which, Christie holds, demonstrates that the governor played no role in the closure of access lanes leading from the town of Fort Lee, New Jersey to the George Washington Bridge. The report identifies Port Authority staffer David Wildstein and Christie aide Bridget Anne Kelly (a known woman) as culpable for the closures; Kelly sent the famous "time for some traffic problems" email to Wildstein, then a Port Authority executive.

But it was the Samson announcement that really made news. Christie explained Samson's resignation flatly: Samson first brought up the idea of leaving least year, prior to Christie's reelection. Christie asked him to stay, and "in deference to me, he did," Christie said. "He just was tired, he had served a long time, he's 74 years old." The impetus now was a set of recommendations in the report, including reforming the Port Authority. Samson, Christie said, agreed with the proposal to split the organization into two parts, and that Christie needed new blood at the agency to make that work.

Left unanswered, though, was the extent of Samson's involvement in the closures. As the report itself notes, when P.A. executive director Patrick Foye ordered that the lanes be reopened on September 13, Kelly and Wildstein exchanged an email, expressing both outrage — and that Samson would step in.

From the report:

At 11:44 a.m., in response to the news of the lane restoration, Wildstein emailed Kelly on their personal email accounts: “The New York side gave Fort Lee back all three lanes this morning. We are appropriately going nuts. Samson helping us to retaliate.” Kelly responded: “What??” Wildstein responded: “Yes, unreal. Fixed now.”

The report explains away the "retaliation" in a footnote.

"In our view, after thorough investigation, we believe Wildstein’s reference to “retaliation” most likely refers to potential actions taken within the Port Authority."

And that's that.

The report does document one way in which Samson fought back against Foye. When a Wall Street Journal report emerged citing an internal memo from Foye, Samson criticized Foye as "stirring up trouble," calling the apparent leak of the memo "evidence of reckless, counter-productive behavior." This was five days after the lanes were reopened. During Friday's press conference, Christie criticized the apparent move by Foye as well, speaking with obvious irritation at Foye having "leaked his memo to the newspapers."

Samson was in the news earlier this month when it was revealed that federal prosecutors were seeking documents from him in relation to the bridge closure. (Samson is a partner at a law firm Wolff & Samson, which has represented the owner of the World Trade Center site, was involved in a development project in Hoboken, and helped craft a bid on a project in Fort Lee itself.)

"It mystifies me on every level why this was done," Christie said about the closures, and he stated his wonder if any motive would ever be found. It seems unlikely that he'll press Samson hard on that question.