Leading article: Why we need the Lib Dems

Under Mr Clegg is a party whose heart is in the right place, and whose head, increasingly, is too

The Independent on Sunday is sympathetic to the values espoused by the Liberal Democrats. Of the three main parties, they are the greenest, the most sensitive to civil liberty at home and the rule of law abroad, and have an honourable record of concern for social justice. Despite our report today that Nick Clegg, the party's new leader, has dropped the policy of advocating early adoption of the euro, the party also remains the most pro-European in the House of Commons. And there are good reasons why a sudden rush to join the eurozone would be unwise, as Chris Huhne, the economically literate home affairs spokesman (who used to be business editor of The IoS), explains in his interview today.

Inevitably, the Liberal Democrats are squeezed in the day-to-day clash of binary politics, even in The IoS. The media tend to concentrate, however much some of us may try to keep the third option open, on the competition between the two parties led by candidate prime ministers. Yet there has not been a time to take the third party so seriously for a decade and a half.

The chances of no one party securing a majority in the House of Commons at the next election are higher than they have been since at least 1992, when John Major was returned by a narrow margin. This may seem a perverse assessment at a time when the Conservatives under David Cameron are enjoying an average lead in the opinion polls of 20 percentage points. But we should recall how sharply popular sentiment has swung since September last year, when Labour under Gordon Brown recorded an average lead of seven points. Nothing can be taken for granted in politics, as Nick Robinson, the political editor of the BBC, discovered on Friday when he began the day by declaring that the threat to Gordon Brown had receded and ended it by reporting new demands for a leadership election.

If Mr Brown were to fall, who knows what effect it would have on the relative standings of the parties? Or, if he continues to pick off the would-be assassins and fights for the right to a second chance with the voters, no one believes that if there really were "a general election tomorrow", as opinion pollsters say, the Conservatives would be 20 points ahead. The peculiarities of our electoral system mean that Mr Cameron needs to be 10 points ahead in order to secure a Tory majority. If he fails to secure that kind of margin, the number of Liberal Democrat MPs, currently 63, is so large and so electorally entrenched that the swingometer has to go a long way across territory marked "hung parliament" before it reaches a Labour majority on the other side.

Mr Clegg is more likely than any of his predecessors since Sir David Steel, a partner in the Lib-Lab pact of 1977-78, to negotiate policy and personnel in government. Yet he came to the leadership of his party at a difficult moment. Not only is reporting of the Liberal Democrats squeezed between that of the two larger parties, but the party's very identity is being squeezed by the Labour and Conservative invasion of the centre ground. Mr Cameron's environmentalism – although its sincerity has been put to the test recently – and the lower salience of Iraq have deprived the Liberal Democrats of two of their most distinctive policies.

Mr Clegg has handled a difficult job well enough. The central thrust of the tax policy that he has devised with Vince Cable, the impressive Treasury spokesman, is right. It is to cut income tax, especially for the lower-paid, and to impose new green taxes designed to penalise pollution and high carbon use. We are more sceptical about their claim to advocate a cut in the overall tax burden. After some years of positioning themselves to the left of Tony Blair's Labour, this looks like an attempt to pretend to be to the right of Mr Cameron's Conservatives. While we appreciate the importance of shedding the image of a "soft touch" high-tax, high-spend party, this may be a symbol too far. To pretend that £20bn a year can be cut painlessly from public spending is the sort of implausible bauble that the Tories tried to put before the electorate in the last three elections, and they were fittingly rewarded for their efforts.

That said, the Liberal Democrats under Mr Clegg's leadership are a party whose heart is in the right place and whose head, increasingly, is too. Mr Huhne's evidence-based approach to criminal justice, for example, ought to influence public policy. In Mr Clegg, Mr Cable and Mr Huhne, the Liberal Democrats have leading MPs who would deserve to sit in any Cabinet selected on merit alone and who, after the next election, may well do so. If they do, they would be likely to contribute to a better government than either of the larger parties could produce alone.