Editor's note: Julian Zelizer is a professor of history and public affairs at Princeton University. He is the author of "Jimmy Carter" and "Governing America." This January, Penguin Press will publish his new book, "The Fierce Urgency of Now." The opinions expressed in this commentary are solely those of the author.
(CNN) -- After months of being beat up by the media about his "Bridgegate" scandal in New Jersey, Gov. Chris Christie is still standing. And there is even some evidence that he might finally be regaining ground.
A new poll from Quinnipiac shows that the governor has narrowed the lead that Hillary Clinton, another possible presidential candidate, has over him in Iowa. His appearance on "The Tonight Show" and at a charity softball game in Yankee Stadium generated some media buzz about the more likeable parts of his personality.
Although his political reputation is a long way from repaired, the idea that the governor might still run in 2016 is back on the table.
How can this be?
A number of factors have helped him absorb the continued blows that he has received from the constant news coverage and ongoing investigations into the events that transpired in the Garden State. The dynamics of the scandal have followed a few principles about surviving scandal politics that have worked in his favor.
1. Avoid the smoking gun: This is the biggest one.
Until investigators have clear-cut evidence that a politician is responsible for the scandal at hand, there is always room for a person to maneuver. In certain cases, American voters are willing to give the benefit of doubt to the person accused -- especially in a heated partisan environment where investigations and accusations often turn out to be unfounded -- until there is evidence in hand that the politician is guilty beyond any doubt.
Whether the evidence is a recording of White House conversations (Watergate) or pictures on Twitter (Weinergate), it's not usually over before this information actually emerges.
The absence of a smoking gun of illegal activity has been very important in this case since, to many Americans, so much of the story -- leaning on politicians, favoring friends and intimidating enemies, making politics a top concern among the staff -- all seem like politics as usual in New Jersey.
2. Time your scandal well: As with everything else in politics, timing is everything when it comes to scandal.
It matters very much when a story breaks. With Christie, the timing was good and bad. The revelations about the bridge began at a real high point for the governor when the media was virtually nominating him to be the Republican nominee on their own. So the impact of negative information was dramatic.
But the story also broke a long time before any presidential primaries started. There is a huge amount of time still remaining until the political season really begins. This means that Christie has had some time for the noise to die down and the worst of the coverage, thus far, has taken place when nationally many people are not paying attention.
The virtues of the scandal happening early are amplified in a rapid-fire media age where reporters turn their attention to the next big story quickly and the readers and viewers are quick to move on.
3. Keep governing: Christie has followed the Bill Clinton playbook.
When faced with bad press and damaging allegations, keep doing the job that you were elected to do. During the past months, Christie has continued to focus on his work in New Jersey. He has been steadfast in his effort to convey the image of a politician most concerned about the challenges facing the electorate rather than the challenges he faces as a result of the scandal. He has also used his fundraising and appearances with the Republican Governors Association to continue to remind voters and member of the party of the assets that he can bring to the table as a party leader.
By doing so, he continues to give the public opportunity to evaluate him a leader in action, rather than just the subject of investigation, and to charge that the accusers are more concerned in scandal than solving problems.
4. Remind your party that they need you: One of Christie's greatest virtues is his party. Even with all the problems that President Barack Obama has faced, the GOP remains greatly damaged. The party has suffered in the polls as a result the way in which Republicans have governed in Congress, as well as continued disapproval of President George W. Bush.
Many of the possible candidates, such as Rand Paul or Marco Rubio, are untested or have serious potential weaknesses, such as Paul's noninterventionism at a moment that things are heating up overseas. Christie receives considerable protection just from the fact that Republicans don't have so many alternatives. Desperate to regain the White House, Republicans have been willing to give him some slack as the story unfolds.
To be sure, it is far from clear whether Christie will ever regain the strength he once had. The recent news about a second scandal involving alleged securities laws violations connected to a major road repair might rekindle public interest in his wrongdoing and potentially produce the smoking gun that has not yet emerged.
But at this point, Christie is still showing some signs of life and remains a player on the political field. He still has the potential to join the list of politicians who have stared scandal in the face and survived politically.