The only thing wrong with the resignation announcement on Friday of David Samson, Gov. Chris Christie’s top appointee to the Port Authority of New York and New Jersey, was that it took so long.

A close associate of the governor, Mr. Samson was running the authority while its employees and the governor’s aides created a traffic jam at the George Washington Bridge in September, apparently to punish the mayor of Fort Lee, N.J., and his constituents. The growing scandal has so far resulted in dismissals of two of the governor’s close colleagues and two other resignations from the Port Authority. But there are still no satisfactory answers as to what happened, why it happened and who ordered it. The $1 million-plus report put out this week was incomplete and unconvincing.

For Mr. Samson, who has been on the authority’s board since 2011, there is more than the bridge scandal. Federal investigators have started looking at whether he lobbied hard for projects that could help clients of his large, politically connected law firm. He should have excused himself from any debate or votes on such matters.

Mr. Christie made the announcement of the Samson resignation at a news conference on Friday after his lawyers issued the report, which absolved the governor of involvement in the bridge scandal. The report barely mentioned Mr. Samson, who would not be interviewed.