I need a pin for my chip. When I left this country they swiped credit cards and let you sign. In the US, where I live now, they still do. Here I find myself in standoffs with waiters.

"I haven't got a pin number," I say. "But it is a credit card. And the food's eaten already." Things usually work out. But not without a grimace.

Increasingly when I return to Britain – I moved to New York in 2003 – I find myself disoriented. With all the new channels, television has become too unfamiliar to bother with; it took me a few clueless moments in the tube to realise that when it comes to public transport in London an Oyster card is too important not to bother with; it took me half a day to work out how to top up my UK mobile phone because my billing address is abroad. I now feel a bit foreign on both sides of the Atlantic.

So developments that people acquaint themselves with over time hit me more abruptly. I'm not here to see things change; I just come back to find they are different.

Watching the election unfold this week felt like that. The erosion of trust between people and the political class, which was well underway when I left shortly before the Iraq war, now seems to be complete.

Travelling around the country I have yet to see anyone wearing a badge or a sticker, or a house with a poster in the window. That's not to say none exists. But in the street I grew up in, in Stevenage, there once would have been several; last weekend there weren't any. It's as if people don't want to be associated with them.

So, far from being a moment of national civic engagement, this election feels completely passive. It used to be something that happened in the country; now it seems to take place primarily in the media. People aren't so much participating in it as watching it all play out on television – it's literally a spectacle.

That was one of the extraordinary things about Gillian Duffy's encounter with Gordon Brown. Neighbours said she usually put up Labour posters, but had not this time. She seemed to come in contact with the election by accident on her way to the shops, and, like Dorothy stumbling from Kansas to Oz, her interaction with it moved her from black and white to Technicolor.

This has produced a paradox. The media are excited. It may be a spectacle, but it's an engaging one. For the first time since 1992 nobody knows what the outcome will be. Huge numbers have tuned into the debates and there's been a steep increase in postal votes and registration – particularly among the young.

On the other hand, voters seem more angry and alienated than ever. Almost every day that the leaders engage with the public they receive a tongue lashing. A young woman challenged Clegg over apprenticeships; a father buttonholed Cameron over his disabled child's access to mainstream education. These aren't hecklers or protesters. They are unorganised and atomised, not arguing but venting. The contempt that Brown showed for Duffy is mutual, open and widespread.

So what has the potential to be the most exciting moment in our electoral history is emerging from one of the most tawdry and depressing periods in our political culture. For now, thanks to Labour's slump and the Liberal Democrat resurgence, unknown voters, a disproportional voting system, three-way ties and local outliers – Greens in Brighton, BNP in Dagenham, Ukip everywhere – the situation is not only unpredictable, it's positively volatile.

When I left Britain I thought people should have been angrier than they were; now they are angrier than I thought they could be. This was patently clear in Bromsgrove, Worcestershire, where public outrage forced the Conservative MP July Kirkbride to resign after she was caught double-dipping on her mortgage.

"The Tories go on about benefit fraud and catching benefit cheats and are caught stealing tens of thousands of pounds of taxpayers' money," said Mark France, who ran the campaign to oust Kirkbride and is now an independent candidate. "The extent of this, contrasted with the impact of the recession, felt like the last straw."

Apart from a hiatus under Labour in 1973, Bromsgrove has been Tory since 1950. Kirkbride, who had been popular, won in 2005 with 51% of the vote and a 10,080 majority. It was about as safe as a Tory seat could get.

This time the Tories are having to work hard for it. An independent Conservative is standing against the official candidate, Sajid Javid. Add Ukip, the British National party, an increasingly confident Liberal Democrat party and other independents into the mix and, while the Tories remain the favourites, the result is anything but assured. Labour is losing votes to the BNP; the Tories are losing votes to Ukip; and the Liberal Democrats are picking up votes everywhere. With the electorate so fragmented, whoever wins could end up with around a third of the popular vote.

Javid is more than just associated with banking. He was the youngest vice-president of Chase Manhattan Bank and then Deutsche Bank's Singapore-based head of global credit trading in Asia. A few years ago that would have been impressive. In this climate it's so toxic his campaign leaflet does not name his profession.

Whether Javid's greatest challenge is that he's a banker or a Muslim is difficult to fathom. His candidacy sparked a rumour that Bromsgrove's Conservative district council and the Muslim Council of Britain have a secret plan to build a mosque in town.

This seems unlikely for three main reasons. First, according to the census, only 0.25% of Bromsgrove is Muslim and the handful I met in the town had never heard of the plan. Second, the Muslim Council of Britain says no such plan exists. Third, Bromsgrove council has never heard of the plan either.

Nonetheless the BNP candidate, Elizabeth Wainwright, is making opposition to the "mosque" central to her campaign. The BNP took out an advert in the local paper promising to "oppose and campaign against any rumoured mosques being built". This advert against the "rumoured mosque"was the source of the rumour.

"I think that's where it emanated from," says the council leader, Roger Hollingworth. "It's absolutely ludicrous and disgraceful. They just made it up to frighten people."

Now questions about the mosque come up on the doorstep. A Facebook site opposing it has 675 "friends". Fitting really, a virtual campaign against a phantom menace.

Living in America, the fact that such tactics can work no longer surprises me. But I never thought I'd see a version of the tea party so faithfully replicated in the Midlands. Rumours like these can only flourish in a vacuum. They thrive in the dislocation between elections, the selection of personnel; politics, the promotion of agendas; and power, the means by which those agendas are enacted. In a truly democratic system there is a causal connection between what you want, whom you vote for and what they do. Where that connection is broken cynicism abounds.

Most of the election conversations I hear are not about whom people would most like to vote in but whom they would most like to keep out. No longer are they being advised to wear a clothes peg on their nose to avoid the unfortunate odours emanating from the party they'll vote for, but to take the peg off so they can remind themselves just how bad the stench is on the opposing side.

For all the excitement about who will win, it is generally agreed the outcome in terms of people's lives will be fairly similar regardless. This is not particularly news to me, either. What seems different are the stakes involved regarding what comes next.

According to the Institute for Fiscal Studies we face austerity measures that will see massive attacks on public services and swingeing cuts in public sector jobs. The Conservatives would deliver the harshest cuts since the second world war; Labour the Liberal Democrats the deepest cuts since the seventies. the difference between the parties is a difference in scale and pace underpinned by a consensus in direction. As events in Greece, Spain and Portugal have shown this week it won't be the voters or the politicians who decide the extent of these cuts, but the markets.

A Financial Times/Harris poll last week found the country divided about cuts, with only half agreeing the public sector should be cut back. But the overwhelming majority, two-thirds, think they will happen regardless of which party is in office.

This is an election about who wins, not what changes. People may want new politics but what they're going to get is a new government with a different mix of parties and maybe a different electoral system.

Back in Stevenage I sat in a beer garden for a few hours with old school friends last Saturday and talked about everything: kids, school, relationships, deaths, old times and aspirations. We talked about why some of us went to university and others would never leave town. We talked about things that mattered. And the election never came up.