The film is based on former White House anti-terror adviser Richard Clarke's memoir of the events surrounding the Sept. 11 terrorist attacks.
Vaughn and Haggis are engaged in talks, but the actor has yet to receive a monetary offer, The Hollywood Reporter said Tuesday.
Sean Penn is expected to portray Clarke, The Reporter said. First, however, he will direct Vaughn, his possible future co-star, in the film "Into the Wild."
Clarke's memoir focuses on the Bush administration's handling of terrorist attacks and the information the government had about the al-Qaida threat, the Reporter said.
Haggis is currently working with writer James Vanderbilt on the screenplay's second draft.