For Jay Roach, Thursday night’s preem of Warner Bros.’ “The Campaign,” starring Will Ferrell and Zach Galifianakis, reminded him of nothing so much as jumping into an abyss.

“I started work without a script, which I had sworn that I’d never do,” he recalled at the afterparty at Hollywood and Highland. “So it was a leap of faith. Will and Zach had told me that they wanted to play candidates running for Congress in North Carolina with extreme political ads, which I knew would be funny.”

Roach began planning the project while shooting HBO’s “Game Change” and admitted that the political drama’s debate scene — where Sarah Palin asked Joe Biden, “Can I call you Joe?” — turned out to be inspirational. “That was very much the basis for our trash-talking scene,” he added.

Roach recalled another inspiration: the cuisine of New Orleans, site of the 12-week shoot. “Oh my God, that was all a lot of people talked about — where they’d gone to eat and what they’d eaten,” he mused.

Popular on Variety

First cut of the film was 3 1/2 hours. Screenwriter Chris Henchy admitted that he and Shawn Harwell wound up writing five times as many jokes as needed. He was particularly pleased, though, that one about the Supreme Court’s Citizens United ruling made it into the final cut, noting, “We kind of slipped that in.”