Johann Hari: We're fixating on Barack and Hillary. Let's listen to the white guy from the Deep South

The world is gaping with awe and disbelief at the prospect of a black or female President of the United States. If George Bush symbolises everything we hate about the United States, Barack Obama seems to symbolise everything we love about the country: its warm openness to immigrants, its shimmering civil rights movements, its idealism. So it feels strange to say it, but reader, it's time to look away from the woman and the black guy towards the white man from the Deep South because he is more left-wing, and more electable, than either of them.

You might remember John Edwards as the plastic vice-presidential candidate standing at John Kerry's wooden side in 2004. Back then, he offered anodyne Clintonian soundbites and centrist platitudes but losing to Bush yet again did something strange to him. It turned him into an angry whistle-blower, exposing the corruption consuming both of Washington's parties.

He explained: "I have seen the seamy underbelly of what happens in Washington every day. If you're Exxon Mobil and you want to influence what's happening with the government, you go and hire one of these big lobbying firms. This is what you find. About half the lobbyists are Republicans, and about half the lobbyists are Democrats. If the Republicans are in power, the Republican lobbyists take the lead, passing the money around. If the Democrats are in power, the Democratic lobbyists take the lead. They're pushing the same agenda for the same companies. There's no difference."

He announced that "the system in Washington is rigged and our government is broken". The failures of US politics not just under Bush, but under Bill Clinton too can only be understood as a result of this endemic corruption. Global warming? It will never be dealt with while presidents and senators have to suck at the oil pump for campaign contributions. Forty-seven million Americans without health insurance? Thank the lavish campaign contributions of the drug and medical companies. Iraq? Look again to the oil donors, the defence donors, the "private military contractor" donors. And on, and on. Edwards adds, "This is personal for me. When I see the lobbyists all over Washington taking our politicians to cocktail parties, the picture I get in my head is of my father and my grandmother going to a mill in South Carolina every day. Where is their voice in this democracy?"

When ordinary American voters hear this, they love it. For decades, the US has been soaked in a fake right-wing populism, where the likes of Karl Rove and Rush Limbaugh and Bill O'Reilly claim to be "looking out for the little guy". In reality they have pushed a corporate agenda that has ramped inequality up to levels unseen since the Depression. But when the voters hear real populism, its appeal is vast. When they are shown clips of the major candidates, Edwards beats the Republicans by a larger margin than either Obama or Clinton.

So why won't he be the candidate? It's not inverse racism, or sexism. It's because the corporations are not giving money to a candidate committed to finally curbing their power, and Edwards wouldn't take it anyway. As a result, he can't afford to run much further, or much harder. Barring a pretty unlikely political breakthrough in New Hampshire or South Carolina, he's out.

This is a political parable that tells us a lot about how US politics works and about what to expect realistically from the successful Democratic candidate. Both Clinton and Obama have chosen to make accommodations with corporate power that will severely curtail any progressive instincts they have. Hillary has inhaled more cash from defence and union-bashing corporations than any other candidate, Democrat or Republican. Her most senior adviser is Mark Penn, a corporate PR man whose firm has represented a slew of monsters, from Shell to the fascist Argentine junta to Union Carbide in the wake of the Bhopal catastrophe. He was fired by Al Gore in 2000 for being too right-wing.

Obama has made similar accommodations. His biggest contributors include Goldman Sachs, JP Morgan Chase, and the telecoms and defence investment firm Henry Crown and Company. It is possible these corporations have suddenly set aside their sole motivating principle, profit, and become interested in liberal progress but it is more likely they expect a return on their "investment". Obama didn't even have to do it. As the investigative journalist Allan Nairn notes, "Obama has the ability to get all the money he needs from the internet, through $50 donations. He actually doesn't need to go to the hedge funds and Wall Street, but he does anyway, because he fears if he doesn't they might think he is on the wrong team, and start attacking him."

Obama, as a state senator in Illinois and then in Washington, has taken lots of important, progressive steps. He managed to build unlikely coalitions to end police torture in Chicago, ban loan sharks, introduce tax credits for poor families, and increase funding to secure Russia's loose nukes. But these are not antithetical to corporate interests; whenever he would have to take them on, he has largely changed the subject.

You can see clearly how corporate donations have skewed Obama's politics. After receiving a fortune from ethanol companies, he became a cheer-leading champion of ethanol. Even though the biofuel has caused a disastrous rise in world food prices. Even though it is worse for global warming than petrol, once you factor in the use of carbon-spewing nitrogen fertilisers.

It is visible, too, in the shape of his foreign policy team. His most senior adviser is Zbigniew Brzezinski, who as Jimmy Carter's Secretary of State oversaw the funding and fuelling of al-Qa'ida in Afghanistan to fight the Soviets. "What's a few riled-up Muslims?" he asked. Obama is also advised by Richard Holbrooke, who was in charge in the 1970s of shipping weapons to the totalitarian Indonesian military so that they could systematically slaughter a third of East Timor's inhabitants. And as a finishing touch, he has on board Dennis Ross, who led the recent assault on Jimmy Carter for stating simple facts about Israel's abuse of the Palestinians.

Don't misunderstand me: Barack would be a far better President than Hillary, and both would be far better than any of the Republicans. They would represent symbolic victories over racism and misogyny. But they will still be in hock to a system of corporate power that will make it very hard to deal with the world's major crises, whether it's global warming, or developing a foreign policy that actually undermines Islamic fundamentalism.

As Edwards puts it, "All the nice ideas in the world won't make a difference if they have to go through this broken system that remains controlled by big business and their lobbyists." For stating this honestly and trying to fight back, Edwards has been priced out of a Presidential race he would and should have won.

j.hari@independent.co.uk