He has retained Chris Lehane, a Democratic Party strategist known as a master of the black art of "oppo," or opposition research, used to discredit detractors. He also hired outside fact-checkers, led by a former general counsel of The New Yorker and a veteran member of that magazine's legendary fact-checking team, to vet the film. And he is threatening to go one step further, saying he has consulted with lawyers who can bring defamation suits against anyone who maligns the film or damages his reputation. [nyt]
It will be interesting to see whether this movie lives up to the hype; and if it is made in a way that convinces the undecideds. These steps to build up credibility seem like a good start.