The last of the paper cups had scarcely been swept up after the Democratic convention when American liberals got the bad news. While they had been celebrating Barack Obama's steamroller ride to the Democratic nomination their candidate's lead over his Republican rival had evaporated, leaving John McCain five points ahead in Reuters/Zogby polls.

Meanwhile McCain's popularity in the red-state heartland took another jump with his selection of the moose-shooting ex-beauty queen, Alaskan governor Sarah Palin, as his vice-presidential running mate. The war hero and gun advocate "hockey mom" are obviously reaching American heartlanders: at some point the left is going to have to learn to reach the same people, especially in the swing states. And to do that they are going to have to learn to speak redneck.

A third of Americans live in the geographic "redneck" south and more than 50% in the cultural south - in places with white southern Scots-Irish values such as western Pennsylvania, central Missouri and southern Illinois, eastern Connecticut, northern New Hampshire, and others never seen as southern. When you look at people in what has come to be called the red-state heartland, most of their values are traditional white Scots-Irish values.

They hold the key to any national election, yet the liberal and alternative media never speak to, or for, them. Progressives dominate the internet, politically speaking, but use it to talk to one another in a closed, politically correct conversation that by definition excludes others, particularly rednecks. I had an editor once, an old-school shot-and-a-beer newsman, who told me: "Joe, don't become a stenographer for the powerful, regardless of their politics or party." I still believe that. It's humanity and a nation we're obligated to, not political junkyism or political correctness.

Especially political correctness that excludes millions who do not see the world in terms of social politics. For instance, if I say on National Public Radio that "rednecks don't vote in their own interests because they are misled by the gun lobby", liberal middle-class America agrees with me. Proof is in the sales of my book. It's been normal practice so long that we rednecks are immune to it, and have come to take a certain defiant pride in the label.

I am an Appalachian native who grew up dirt-eating poor. Yet I have managed to live a couple of decades in the middle class as a news reporter, magazine editor and publishing executive. I know the liberal middle class is condescending to working-class redneck culture - which is insulting, but not a crime. The real crime is the way corporate conservatives lie to my people, screw us blind, kill us in wars and keep us in economic serfdom.

The good news is that many lower working-class people are starting to figure that out. If we bothered to cover redneck culture we'd be surprised to find how many progressive rednecks, what I call leftnecks, are out there. America's media caste, however, is put off by the way these folks look and sound, and by their unpredictable opinions. It's happy to deal with the rural red-state working class as long as it remains out there somewhere in "the heartland", a place to be polled and surveyed by Gallup to fuel self-absorbed political punditry.

Those in the media are granted entitlement to be the one voice, defining America to the many. And they keep that entitlement as long as they maintain false objectivity and keep working-class people politically in the dark. That is not difficult. Every daily newspaper has a business section, but none has a labour section. My European friends, this is no accident. No accident at all.

· Joe Bageant is the author of Deer Hunting with Jesus. He will be speaking at the South Bank Centre in London on September 9 southbankcentre.co.uk