The election campaign has not yet officially begun. Yet public disengagement from politics is already a central theme. And nothing in the early skirmishes yet suggests that the parties will reinspire the disillusioned. We can expect to hear a lot about a potential crisis of democratic legitimacy if turnout drops below 50 per cent. But if we really want to tackle this problem we must be far bolder than we have been so far.

Every pressure group has its own pet scheme to deal with political disengagement – be it a democratic Lords, votes at 16 or electoral reform. The government tries all-postal ballots and putting polling stations at supermarkets to try to edge turnout up. But all of this activity dodges the real problem, which is about the culture of our politics. Tinkering with institutions won't work unless we address the underlying cultural malaise.

The fact is that we have lost sight of what politics is for. The Electoral Commission recently found that 'many people seem to see "politics" as an obstruction to, rather than the means of, proper government of the country'. For most people, politics is simply what politicians do – and many see the politicians as the problem. But it is not just the apathetic masses who fail to acknowledge what politics is about. Party leaders talk of finding new ways to connect, and the media churn out stories about apathy, but neither politicians nor journalists adequately consider how they themselves contribute to the problem.

Politics is fundamentally about difficult choices. It is the way in which complex societies weigh up competing demands and choose between them peaceably. In this process there must always be losers. But the alternatives are much worse. Politics, with all of its faults and necessary imperfections, needs defending. Yet those involved rarely stop to do this.

The threats to politics today are rather different to those when Bernard Crick penned his classic treatise In Defence of Politics forty years ago, at the height of the Cold War. Indeed today's threats arise in part from democratic success. But the apparently softer challenges to politics today - consumerism, the culture of the permanent campaign and an aggressive media culture, are potentially even harder to counter. Together, they are threatening the very ethos of politics itself.

A consumer society which constantly tells us that we can indeed 'have it all' is utterly at odds with the political ethos. Yet politicians adopt the dominant consumerist language to talk about public services, and parties seek to extend their 'offer' in a political 'marketplace'. A political culture where 'the customer is always right' rarely recognises that governments have only the resources which citizens consent to give them or that Ministers cannot 'deliver' on reducing traffic growth unless voters leave their cars at home.

After the tsunami disaster, we heard of the 'generosity' of the British public, contrasted with the 'meanness' of its politicians, and so a sheepish Blair promised to 'match' the donations of the public, as if the government's money were his own. The Prime Minister will come into contact with more angry voters over the coming weeks, yelling, like one at a Birmingham hospital in 2001, 'You are just not prepared to pay for it'. Yet he is unlikely to retort, as perhaps he should, 'We madam, have only the money that taxpayers consent to give us: it is therefore you who are not prepared to pay for it!'.

The parties seek to make short-term gains from negative campaigning. Labour made much of Tory sleaze, at which point trust in politicians slumped, and has never properly recovered. Now Michael Howard tells us we have 'a grubby government' and Charles Kennedy stokes the sense that 'they are all as bad as each other'. It may pain politicians to acknowledge, in the heat of battle, that even their opponents are generally honest and hardworking, and driven by belief rather than personal gain. But if they fail to do so they will only drag the reputation of the political profession further and further down.

The media fuels the adversarialism of British politics, which has moved from parliament to the TV studios. It is simpler to create the impression that there are two sides to every issue, rather than present the truth: that most issues are complex and multi-faceted. For example during the fuel protests Ministers were harangued by motoring groups on the Today programme until there was a compromise on fuel duty. Then the following morning, environmental campaigners were brought on to accuse the government of selling out. This approach absolves the public of all responsibility, turning us into bystanders rather than citizens. It is the politicians who are left to get the blame from all sides.

The only answer is to build a new culture of politics. We are not just a wealthier society – better able to consume – but a better educated society which should be able to engage in more sensible political debate. Adapting politics to consumerism is doomed to fail – it in fact exists to resolve the very questions that the market cannot. Instead we must admit that politics is hard. Our only hope for reviving it is for politicians to start being more frank with us about the challenges they face, and our own role in building the better society that we seek, and to stop talking down their own profession. In short is time for British politics to grow up. Otherwise it is only likely to continue its slow decline.

• Meg Russell is Senior Research Fellow at the Constitution Unit, University College London. Her pamphlet Must Politics Disappoint? is published by the Fabian Society on 21st March 2005.