Those emails suggest that Mr. Samson, even though his vast agency is in charge of the region’s ports, airports, bridges and tunnels, was unconcerned that thousands of people might have been trapped in a colossal traffic jam that was created to punish a Democratic mayor who would not endorse Mr. Christie, a Republican, for re-election. But the emails show Mr. Samson as very concerned about politics, specifically that Patrick J. Foye, the executive director of the Port Authority, was trying to get to the bottom of the jam.

“In this case, he’s playing in traffic, made a big mistake,” Mr. Samson wrote about Mr. Foye, who was appointed by the New York side of the bistate agency.

The scandal has already cast a cloud over what many see as the final role of Mr. Samson’s political life. Perhaps with that in mind, he has explored the idea of retiring from his post in recent days, according to government officials who would not speak on the record. He has denied this, saying only: “The story is incorrect.” The lane closings have already resulted in two resignations, and Mr. Christie’s decisions to fire a top aid and cut ties with a second. Mr. Christie has denied any knowledge of the scheme.

Mr. Samson, who declined to be interviewed for this article, has been close to state officials for decades. He was an adviser to former Govs. Thomas H. Kean, a Republican, and James J. Florio, a Democrat, and was chief counsel to the New Jersey Turnpike Authority during the 1980s.

But his alliance with Mr. Christie appears to be the strongest. He was counsel to Mr. Christie’s 2009 campaign and led his transition committee. And Mr. Samson was among the close advisers who went to Arizona with Mr. Christie in November, when he took on his new position as chairman of the Republican Governors Association, and he accompanied him to the Republican National Convention in 2012, according to an associate.