We’re used to politicians talking out of both sides of their mouths. "The Campaign" is a political comedy that attempts that feat.

It’s a rude and crude farce that takes broad swipes at the political system and the people who manipulate it. It’s not subtle about attacking those alleged election-buying billionaires the Koch brothers (called the Motch brothers here). The campaigners themselves are basically puppets — one a crass, lazy Democrat given to giving in to his basest instincts, the other a startlingly ill-informed Republican whose values give way to a cynical makeover to make him more presentable to the North Carolina voters he’s appealing to.

And the voters themselves are ranting, red-faced rubes who can’t stop fulminating long enough to realize that calling the other guy’s pug dogs "communists" is about the silliest thing ever.

‘THE CAMPAIGN’ Rated: R Opens today

But this R-rated comedy, directed by Jay Roach, tries to have it both ways. It straddles the "fair and balanced" fence, making the naive, effeminate Republican (Zach Galifianakis) an idealist backed by the evil Motch brothers (Dan Aykroyd and John Lithgow, doing a "Trading Places"-evil-rich-siblings thing) and the Democrat (Will Ferrell) a boozy, womanizing cynic whose idealism evaporated in high school.

The worst thing about the Republican is his stupidity. Galifianakis makes Marty Huggins, a Hammond, N.C., tour guide who is nothing but a disappointment to his racist, vile dad (Brian Cox), a likable daft. The plump, prancing Galifianakis makes Marty the sort of guy you’d love to take to Chick-Fil-A. Or not. The film’s earliest comic shock is when we see he has an equally plump wife and kids.

Ferrell is ferociously, hilariously unlikable as Cam Brady, the four-term incumbent. Whatever his merits as a congressman, the very idea that he has to run for re-election, and against this idiotic sissy to boot, makes him nuts, leading to one gaffe after another.

Then these two would-be good ol’ boys get into the drawlin’ trash talk: "What’s the difference between your mama and a washin’ machine?"

Marty, guided by a nasty political infighter (Dylan McDermott), has a killer campaign slogan to take him to Washington. "Bring your brooms," he says of D.C. "Because it’s a MESS."

Director Roach throws filthy-mouthed kids, sister-marrying "born again" Christians, sex in port-a-johns and wardrobe malfunctions at us. The campaign ads — tested on the candidates — are jaw-droppers, full of whoppers and "Jesus" bromides and porn. The candidates themselves are the biggest mess of all. Marty ineptly panders to the Jewish vote in a synagogue while Cam joins a black Baptist church choir.

But movies that step on that third rail of filmgoer appeal — politics — always pull their punches. Think of "Swing Vote," which had a few stinging shots, but no spine, the last election cycle.

Here, the debates have a few chuckles. Challenge your opponent to recite "The Lord’s Prayer," and hope his campaign aide (Jason Sudeikis, in his one good scene) has to mime out the words from the back of the auditorium. Most of the laughs come from the shocks, which can be shocking. (Oh no, he did NOT just punch a baby! That DUI did NOT just end with him stealing the cop’s car!)

And the actors are game. Ferrell is in full "Anchor Man"-meets-"Ricky Bobby" mode here, loud, abrasive, big-haired and outrageous. And Galifianakis refines the mincing ditzes he’s made his shtick. But steering clear of anything that might turn off some potential ticket-buyers makes the film feel as focus-grouped and watered-down as the very campaigns it aims to spoof. A little about Chinese child labor, a bit more about rich people running the works behind the scenes by owning voter-machine companies, are as edgy as it gets.

The one unadulterated, fall-on-the-floor running gag in Chris Henchy and Shawn Harwell’s script is played to perfection by Karen Maruyama. She’s Mrs. Yao, the maid for Marty’s bigoted dad, forced to talk in a Stepin Fetchit sing-song straight out of "The Help" to remind the old man "of the good old days" — when Jesse Helms was a North Carolina icon and all was right with the South. Maruyama kills, so much so that they bring her back for an ill-considered bit in the finale.

By that time, despite landing more than a few laughs beforehand, Roach must have known he needed the help.