Trenton, New Jersey (CNN) - Another top ally of New Jersey Gov. Chris Christie has resigned amid a political scandal that has roiled the Republican's administration and clouded his potential presidential prospects.
Christie announced at a news conference Friday that David Samson, who chairs the Port Authority of New York and New Jersey, stepped down earlier in the day, effective immediately.
"He's 74 years old. He's tired. He's served a long time," Christie said of Samson, a one-time state attorney general and a powerful private attorney.
The resignation is the latest fallout from the George Washington Bridge lane closures of last September that snarled traffic on the New Jersey side and led to allegations of political retribution against the Democratic mayor of Fort Lee for not endorsing Christie's reelection.
Christie faces press again
Facing reporters' questions for the first time in more than two months, Christie repeatedly cited a report he commissioned that this week cleared him of any role in the several days of traffic jams near that nation's busiest bridge.
Responding at times with his trademark gruffness, Christie also acknowledged the controversy had shaken his confidence due to alleged links of top aides and associates to the lane closures.
People he "trusted and relied on" let him down and therefore, his administration let down the state, Christie said, adding: "Of course that shakes your confidence."
Separate federal and state investigations continue, and the scandal has lowered Christie's poll numbers as he contemplates a possible presidential run in 2016.
He insisted Friday the current poll numbers don't matter and voters would be little concerned about the bridge controversy in two years.
However, Christie also tried to distance himself from the main figures in the scandal, including Bridget Kelly, his deputy chief of staff whom he fired in January, and David Wildstein, a New Jersey appointed executive at the Port Authority who has resigned.
Traffic study or political retribution?
While maintaining that a traffic study of some kind caused the gridlock, Christie said this week's report raised questions about "some type of nefarious or inappropriate motivation for it" on the part of Wildstein and Kelly.
Christie used his opening statement to announce the resignation of Samson, who had come under increasing pressure to step down because of the appearance of an inherent conflict of interest.
Samson served as chairman of the board of commissioners - a part-time oversight position for which he received no compensation - while the law firm he founded represents several clients who do business with the Port Authority.
A Christie appointee, Samson previously said he recused himself from board votes when they involved business with clients of that firm.
While not accused of any wrongdoing, Samson has been subpoenaed by a legislative panel to turn over documents as part of its investigation into the traffic mess.
Last month, he issued an apology as chairman of the Port Authority board for the inconvenience caused by the traffic gridlock over five days in September.
An interim chairman would get chosen from the current commissioners, Christie said, and he would then seek a permanent replacement.
He also said he accepted the recommendations in this week's report for reforms at the Port Authority, and wanted to explore the idea of breaking it up to create separate entities for New York and New Jersey.
Christie's appearance was his first news conference since January 9, when he answered questions for nearly two hours about the bridge controversy that was starting to make national headlines after simmering as a local controversy during the fall election.
The day before, a team of lawyers hired by Christie's office released its internal review of the lane closure controversy.
Unlike the January appearance, when a subdued Christie appeared to be facing possible political destruction, he was his old feisty self and engaged in some sharp exchanges with reporters.
He criticized one reporter's question as being beneath the profession and refused to answer another because he said the question was based on false assumptions.
The report blamed Kelly and Wildstein, and backed the governor's denials that he knew anything about the gridlock until after it occurred. Christie has said he knew nothing about any political mischief by members of his administration.
Kelly refused to cooperate with the review ordered by Christie, but her attorney released a statement Friday saying she would "provide truthful and complete answers" to the ongoing federal investigation if she received "appropriate procedural safeguards" - presumably immunity from prosecution.
The statement also criticized the report commissioned by Christie for "venomous, gratuitous and inappropriate sexist remarks" about her, saying such attacks were a "preemptive strike" intended to discredit her.
The U.S. Attorney's office is investigating the scandal as is a state legislative committee.
"Venomous, gratuitous and inappropriate sexist remarks"
Christie acknowledged Friday that the report was "limited in small part by some of the access that they had and didn't have to certain people." But he added the document exonerating him of any wrongdoing was exhaustive and thorough and he knew it was going to be criticized "no matter what."
A key entry in the report released by Randy Mastro, who led the internal investigation, found that Wildstein apparently told a top official with the governor's office in Trenton that he informed Christie at a public event about the lane closures as they were occurring.
But the report said Christie "does not recall" any conversation with Wildstein and it all wouldn't have "registered" anyway because the governor "knew nothing about this decision in advance" to close traffic lanes.
The report also examined the claim that Christie had created a "culture" of bullying adversaries and found it "unsubstantiated."
Investigators conducting the internal review were not able to speak with Wildstein, Kelly or other prominent figures in the scandal.
Wildstein also has refused to testify before legislative investigators, while Kelly is fighting her subpoena in court.
The review also found that Christie campaign manager Bill Stepien and Port Authority Executive Director Bill Baroni, another Christie appointee, knew of the plan to close the lanes in advance, but there was no evidence uncovered that the two men knew why.
CNN's Tom Cohen contributed to this report.
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