Gary Oldman and co-producer Douglas Urbanski complained, after the film was released, that the film was changed from the more balanced script by Dreamworks Studios to reflect the liberal politics of the studios head at Dreamworks (Steven Spielberg, Jeffrey Katzenberg and David Geffen). The British Oldman, who according to long-time business partner Urbanski is "the least political person I know", was simply contending this since he didn't enjoy how negatively his character was portrayed. Dreamworks vehemently denied tampering with the film.
Director Rod Lurie aid he first offered the lead role of President Jackson Evans to Paul Newman and then to Gregory Peck. Newman--then in semi-retirement--declined, as did Peck, claiming he was 'too damn old' for the role. In response, Lurie rewrote President Evans's character to be younger, and then cast 'Jeff Bridges'.
The trivia item below may give away important plot points.
An entire subplot involving Laine Hanson's father, Oscar Billings (Philip Baker Hall) was dropped in post-production. In it, the character was given more depth and portrayed as a corrupt former governor, who used his influence and money to help his daughter get a Senate seat (without her knowledge). This information leaks and Oscar, guilt-ridden, kills himself in shame. Rod Lurie cut this out because of time and because he felt the audience would have a hard time believing the senator could beat these nepotism charges and get confirmed.