The city emerges from the Arizona desert like a sprawling conurbation in search of an environmental impact assessment. Over the last 20 years Tucson's population has grown by 27% as thousands came looking for land, work and retirement. The two major demographic forces here for more than a generation have been those who came to start their lives over and those who came to die.

The surrounding desert became a blank canvas for new building. Coachloads of speculators were driven in from California to buy a piece of the real-estate action. Between 1998 and 2006 house prices doubled. When economic gravity intervened, parts of the country like this fell hard. House prices in Tucson are down to the level they were in 2004. Since foreclosures in the state now account for almost half of all home sales, they have much further to fall. A state that was never very wealthy now has the second-highest poverty rate in the country. One in five are poor: roughly the same proportion that have no health insurance.

When the CNBC correspondent Rick Santelli became the first to call for a "tea party" to prevent the government bailing out the "losers' mortgages" in February 2009, these were the kind of losers he was referring to: those unlucky enough to have just signed on the dotted line when the good times stopped rolling. "This is America!" he yelled from the floor of the Chicago stock exchange. "How many of you people want to pay for your neighbour's mortgage that has an extra bathroom and can't pay their bills?" The traders booed.

The only thing more stunning than the contempt that Republicans in general and the Tea Party in particular have shown for working- and middle-class Americans during this recent crisis is the propensity of those same Americans to back them.

The issue here is not false-consciousness – the notion that people do not know what is right for them. There are legitimate philosophical reasons why people – including the poor – might be in favour of lower taxes and less government. But polling shows that when it comes to poverty, the elderly and education, if anything people want to do more rather than less.

But that is not what they are going to get. It is the Democrats' failure to sufficiently deliver that has provided the fertile ground for this cynicism to grow. But it has been the right that has been providing the manure and tending the plot. In terms of policy and rhetoric the country has moved beyond a stage where reasonable people might differ, to the realms of fantasy, calumny and idiocy.

The Republican governor of Arizona, Jan Brewer, is opposed to the stimulus bill which, among other things, is weatherising homes for the poor and putting solar panels on government buildings in her state – creating work for thousands of people in a place that has 271,400 fewer jobs since the recession. But nine out of 10 dollars of stimulus money – about $443m – remains unspent. When asked for her opening statement during a televised debate, Brewer stopped halfway through, stared blankly into the camera and started giggling. Yet, she holds a double-digit lead over her Democratic challenger.

In West Virginia the Republicans were recently exposed putting out a call for actors with a "'hicky' blue-collar look" who could appear in an ad as "coal-miner/trucker types" trashing the Democrat, Joe Manchin, for his affiliation with Obama. Manchin, currently one of the most popular governors in the country, is trailing his Republican opponent by three to five points.

In a political culture where basic, verifiable facts cease to matter, political debate is inevitably debased. Add to that a polarised media, in which people access the truth they seek, rather than the one that exists, and it has given rise to bespoke realities: people don't just think different things, they know different things. And some of the things they think they know are just wrong.

For all his faults, if Obama can only convince a third of Americans he is a Christian and less than half that he was definitely born in the US, then what chance does he have of convincing them of his plans for healthcare or revitalising the economy.

A short drive from Tucson, Jesse Kelly, the Tea Party Republican candidate for Arizona's 8th district, takes his place in the Vail town parade. This would seem like unpropitious territory for a candidate who favours eliminating the minimum wage, privatising social security on which the elderly rely, and paring government down to its bare essentials.

However, with less than a month to go before the midterm elections, Kelly is in serious contention against the incumbent Democrat, Gabrielle Giffords. She is a moderate Democrat who supported healthcare reform, the stimulus bill, and carbon trading – all lightning rods for Republicans. Nonetheless, Giffords' team were delighted when Kelly won the primary against a far more moderate candidate, claiming in an August memo that "their prospects for re-election had brightened significantly" with the selection of a more extremist candidate.

The fact that Giffords and Kelly are locked in such a tight race – the respected Nate Silver gives Giffords a 51.7% edge over Kelly – raises two contradictory questions about the current electoral moment in the US.

The first is why Kelly is not doing better. This district voted for George Bush twice – in 2000 and 2004 – and John McCain in 2008, and had a Republican Congressman until 2006, when the Democrats took the seat. That year was hailed as a landslide for Democrats. If this were also going to be a landslide, the Republicans would have sewn up the district by now. But they haven't – at least not yet. So while large numbers of Democratic seats are in play, Republicans have put fewer beyond doubt at this stage than they had hoped. The situation is incredibly volatile and could well be decided by slender margins in several places.

The second, more enduring, conundrum, is why Kelly is doing as well as he is. Giffords is a strong candidate with a lot of money. In a constituency where around 40% of the voters are 60 or over, Kelly has derided Medicare – the government programme that assists seniors with their healthcare – as the "public dole". That alone should have thwarted his chances. Moreover, Arizona's 8th district would appear to need government more than most. Sprawling over 9,000 square miles, it has a population less than two-thirds the size of Birmingham in an area considerably bigger than Wales. Left to its own devices, no market would build schools, roads or sewage works here.

Back in Vail, Kelly's supporters stand outside the Guns and Ammo store with two flags flanking a banner bearing his name: the first is the stars and stripes, the second the Tea Party emblem of a coiled snake and the words "Don't Tread on Me". Kelly takes his place in the parade behind a family in period costume and ahead of some men on Harley Davidsons. His positioning is apt.

When Tea Party supporters talk about "taking our country back", they are – in part – expressing nostalgia. They literally want to take it backwards to a past when people had job security, and a couple on a middle-class wage could reasonably expect their children to have a better life than their own. The party they have been voting for and the candidates they are supporting now have actively and openly worked to undermine those aspirations. Their frustration at the Democrats' inability to deliver on their promises should be eclipsed only by their fear that the Republicans do manage to deliver on theirs. No wonder they are so angry. They keep treading on their own toes.