Leader: Today's forecast: unsettled, with scattered reforms

How do we decide what is important? No, this is not a question about the meaning of life, but about the way a modern democratic society orders its priorities. Because it is obvious that this kind of election campaign is not the best way to do it.

The language of priorities is not just the religion of socialism, it is the belief-system of politics generally. It is the language of political speeches, of manifestos and opinion polls (and often of newspaper leader- writers). But there is a disjunction between what are often described as the "most important" issues and what really concerns people in the day-to-day.

Perhaps this gap explains the dreamlike unreality of the election campaign, which has bounced about between central and side-issues in an alarmingly casual way. Mostly, it has not even been about the issues that the politicians profess to think are "important".

Tony Blair has, with an American trick of rhetoric, described his top three priorities as education, education and education. And yet his policies for our schools and colleges have hardly featured in the campaign. In the opinion polls, unemployment is usually at the top of the list of "most important" issues, yet Labour's plans to get a quarter of a million people off welfare and into work are only just beginning to come under scrutiny. Like our professed willingness to vote for higher taxes to pay for increased spending, this seems a classic area for voter hypocrisy, because there is no evidence that plans to tackle unemployment actually change the way anyone votes.

A good case has often been made out that the advent of a single European currency presents our democracy with the biggest decision it has had to take since the war. Yet it only began to feature in the campaign yesterday, and then (inevitably?) only as a "Tory split" story.

Meanwhile, in the real world this past week, the subject on most people's lips (and on their cancer-endangered skins) has been the weather. This is not merely the English living up to their national stereotype, but an undeniably "important" issue. Why has summer arrived two or three months already? It is well established that population growth and economic activity has changed the climates, and will go on doing so for decades. But apart from some jarringly apocalyptic words from John Gummer, the Environment Secretary, the growing understanding of cause and effect has yet to make the connection to policy, political argument and action. Nor will it by 1 May. There are some things our political process simply can't cope with.

This is not to say that the election is pointless, or somehow anti-democratic. It is simply that in the absence of big policy questions between the parties, the purpose of the campaign is primarily as a character test. It is about choosing which team can best be trusted (or distrusted least) to make the best (or least bad) decisions about the "important" issues, as they come up, and whatever they are. In the analogies of political science, the voters in this election are not going shopping, having to choose between baskets of policies, but are choosing an investment trust, in which the policies of the management team are less important than their record, and their record in turn less important than their general dependability.

On this model, the weakening of party loyalties is not simply a product of the convergence of the main parties on the centre ground of politics, but a response to the dispersal of voters' interests and causes.

The environment is typical of the categories of problems that cannot easily be organised into two rival world-views, between which the voters can choose using the first-past-the-post system. The green debate takes place largely outside the party-political process, yet issues such as climate change are utterly political. They can only be tackled by collective action, at national and international level, and the priority accorded to them can only be decided by some form of democratic decision-making.

Other excluded issues are beginning to burst the seams of our restrictive, antiquated system. The Referendum Party, the People's Trust, the Pro-Life Alliance and tactical voting campaigns are evidence that some people's passionate concerns are not being accommodated.

The trouble with all these is that they tend to be top-down rather than bottom-up initiatives. But we should not be depressed about this, because it implies that a new politics is waiting to be born. It might need top- down change to stimulate it, but it would arise naturally from a concerned and active citizenry if it were not stifled by the present set-up.

That is why reform of the House of Lords, self-rule for Scotland, Wales and London, and a referendum on the voting system, would be liberating and transforming. Lords reform alone would upgrade the forum in which important issues can be debated. Above all, however, a reformed voting system would give expression to dispersed competing interests and allow the people to make more meaningful decisions about what matters - as well as simply about which team gets to walk into Whitehall. So you could say constitutional reform - reform of the way Britain is governed - is actually the "most important" issue of this election. It affects everything else.