With the American presidential race getting scarier by the day, surely only the savage iconoclasm of Hunter S Thompson could do justice to the election’s madness and mendacity. Just imagine the ferocious spleen the author of Fear and Loathing on the Campaign Trail ’72 (his account of that year’s Nixon-McGovern contest) would have unleashed on god-fearing, moose-hunting, hockey mom Sarah Palin, aka “Caribou Barbie”.

In the absence of the great Gonzo journalist, who you will recall blew his brains out with a .44 calibre pistol in 2005, it appears we will have to make do with Swing Vote, a good-natured and mildly satirical comedy from little known writer-director Joshua Michael Stern, maker of 2005’s Neverwas (Neverwhat?).

Stern’s movie stars Kevin Costner as a loveable loser named Bud Johnson, a boozy slacker who lives with his precocious 12-year-old daughter Molly (played by the equally precocious Madeline Carroll) in a battered trailer in the town of Texico, New Mexico (which sounds made up but does in fact exist). Bud has promised the civic-minded Molly that he will vote in the upcoming presidential election but passes out drunk in his truck instead.

A series of contrivances then unfold, with the outcome that the entire election hinges on Bud’s un-cast vote. As a result, the media descends on Bud’s home, and so do Republican incumbent Andrew Boone (Kelsey Grammer) and Democrat challenger Donald Greenleaf (Dennis Hopper). In the days that follow, as swarms of reporters hustle for a scoop, Boone and Greenleaf, and their slippery campaign managers (Stanley Tucci and Nathan Lane), bend themselves out of shape in an effort to sway Bud’s decision.

A series of hilarious spoof campaign ads show the consequences. Bud babbles a half-baked thought; the politicians pounce on it; and end up flip-flopping their most deeply held values. So Republican Boone comes out in favour of gay marriage and ecological preservation, while liberal Democrat Greenleaf starts making anti-abortion and anti-immigration pronouncements.

In the end, though, the movie is too frightened of alienating half its audience to take sides; so cautious about offending either the Red states or the Blue states that it sits on the fence. (Can a political satire be apolitical?) A bruising scene involving Mare Winningham as Molly’s estranged mother hints at the true desperation of America’s “working poor”, as Molly accurately describes Bud, but overall the movie prefers to aim for a mood of Capraesque uplift. Ultimately, Swing Vote, like Costner’s protagonist, is too benign to go for the jugular and settles instead for tickling us gently in the ribs.