IN A gloomy corridor behind the kitchen of the Capanna coffee shop, in downtown Iowa City, presidential candidate John Edwards leans against a wall.

A dozen or so locals who have sneaked into the back of the building wait with him as he is introduced to the audience.

Suddenly, on cue, he bursts into the room, grabbing outstretched hands and greeting supporters before he takes up a position in the midst of the crowd and delivers an impassioned speech about inequality in the US.

The figures he quotes provide a glimpse of the stark balance sheet of life for many in the world's richest economy - 37 million Americans waking up in poverty each day, 47 million without access to health care, 200,000 veterans sleeping rough every night.

At the same time he chides the multi-billion dollar profits of big oil firms and other corporations while their workers suffer pay cuts and poor conditions.

His message is rousing, barnstorming stuff and goes down well with his supporters, hundreds of whom have squeezed into the small café. I have to climb on to the condiment counter to see him fielding questions from the throng.

This took place two days before voting in the Iowa caucuses, which last month kicked off the process of deciding the next US presidential nominees, and all the candidates were on the stump.

The whole of Iowa seemed abuzz with excitement at the four-yearly ritual, during which the sparsely-populated rural state delivers the first verdict on the men (and woman) who would be president.

Earlier that day I had heard Barack Obama speak at a hotel in a nearby town. In an overflow room, we listened to the youthful senator speak of pleasing, meaningless concepts: "hope" and "change".

A brilliant orator, he seemed genuinely to enthuse the young audience. Despite being light on detail, his positive message played well to Iowans; it has continued to do so as throughout the race and he is now neck-and-neck with Hillary Clinton.

All the Democratic candidates bemoaned the state of the "shrinking" middle class caused by the Bush administration's welfare policies for high-earners, while at the other end of the scale more people slip into poverty.

Health care has also been a central issue in the election because so many people are without it. It is difficult to believe that the wealthiest country in the world does not have this basic a safety net for tens of millions of its citizens. But neither Obama nor Clinton proposes anything like what we enjoy with the NHS. They rely instead on the sticking plaster solution of extending individual health insurance schemes.

Of course, health care, like the squeeze on the middle class, has at its root the question of the division of the spoils in a country where the top 300,000 individuals now make more than the bottom 150 million combined. That is a question Clinton and Obama don't want to address and it has been the elephant in the room throughout the election.

Edwards, who has now dropped out of the campaign, raised these issues in an undeniably populist campaign, speaking of the "Two Americas". There was a certain irony in this coming from a multi-millionaire former lawyer whose links to hedge funds, $400 haircuts and 27,000 sq ft mansion embarrassed him during the campaign. But the point still stands.

During my time in the country, I visited Chicago and stayed with some friends in the city's South Side, a sprawling area synonymous with poverty and racial division. As we drove past rows or boarded-up shops, rundown blocks of flats and dozens of churches, our hosts told us the make-up of the different areas. Racial classification seemed to change street by street.

Ever present, in the distance, was a forest of shimmering skyscrapers; looming towers that would be forever remote to most of the area's inhabitants.

The contrast seemed to sum up perfectly the fracture that exists, and is widening, in American society.

The race for the White House now looks likely to become the most expensive in US history, with the candidates predicted to top $1 billion in spending.

With the corporate giants and the country's wealthy elite picking up the bill, the change that Obama and Clinton both talk about is almost certain to be a mirage.