On the surface and judging from the trailers The Campaign should've been a goofy hoot since stars Will Ferrell and Zach Galifianakis are willing to debase themselves mightily for a laugh, but the results are a muddled mess.
Ferrell is a crude dumbass who is running unopposed until a evil scheme by the Motch brothers - obviously meant to represent liberals favorite demons, the Koch brothers (whose names are pronounced "Coke", not that liberals are concerned with details like that and the brothers are Libertarians, not Republicans) - to set up a Chinese sweatshop in the district (don't ask, it's impossible in the real world) has them put up town oddball Galifianakis to challenge him. Supposed hijinks ensue.
The fundamental problem with The Campaign is that it's not very funny. There are a few spots here and there, but your midline sitcome will make you laugh more in less time this this does. A greater problem is the film's muddled tone; it doesn't know if it wants to be the lowbrow comedy it was advertised as, a liberal screed against the evils of anything not liberal and socialistic, or a acid-blooded satire about the generally corrupt nature of politics. By trying to be everything, it ends up being nothing.
For a far better cynical take on politics and media manipulation, check out Wag The Dog which has the advantage of being written by David Mamet.
Score: 3/10. Skip it.