Although the poster depicts the two lead characters facing off in front of Capitol Hill in Washington, D.C., almost the whole film is set in and around North Carolina where the two characters live and are campaigning. There is a single post-credit sequence set in Congress.
Zach Galifianakis' uncle Nick had been a North Carolina Congressman who lost the 1972 Senate election to Jesse Helms. Plus, it is stated in the film that Galifianakis' character's father was the former campaign manager to Jesse Helms.
Though not directly referenced, the Motch brothers are based on the real life Koch brothers. David H. Koch and Charles G. Koch are major contributors to conservative policy and advocacy groups in the U.S.
WWE wrestler Mike 'The Miz' Mizanin had filmed a scene where he would introduce Cam Brady (Will Ferrell) but the scene was later dropped before the movie's premiere. However he can be still seen in the background in a later scene.
During the end credits when Marty Huggins (Zach Galifianakis) is mentioning the aliases used by Tim Wattley (Dylan McDermott), one of the names he says is Dermot Mulroney. In real life, McDermott is sometimes confused with Mulroney due to the similarities in their names.
Cam Brady's slogan "taking care of business" is more than a simple reference to a hit song, it's a promise to look out for corporate interests before citizens. It is also a reference to Scott Walker (of WI) who used the slogan "Wisconsin is open for business". He was heavily funded by the Koch brothers which the Motch brothers are mentioned to represent.
This is the second time Dan Aykroyd appeared on a political themed comedy film. In the 1996 film My Fellow Americans, he was the incumbent president; here, he plays one of the lobbyists who force Marty Huggins to run for Congress.