Leading article: Lib Dems: Credit where it's due

When Lehman Brothers went bust a year ago over- engineered financial derivatives were not the only things that went down the plug hole. Any hopes that Nick Clegg might have had of getting decent coverage of the Liberal Democrats disappeared, too. As soon as the news hit on the Monday of the party's annual conference their agenda was sucked into the black hole known as the credit crunch.

This year, he must have his fingers crossed that the Sugababes or Katie Price do not steal all the headlines. The party certainly deserves a fairer hearing than it has received over the past year.

Since it was founded, this newspaper has been sympathetic to the Lib Dems, and over the last 12 months the party under Mr Clegg has proved itself worthy of that approval. He and Vince Cable, his deputy, have done a good job of being straight with people without escaping too easily into the irresponsibility of opposition. They have been more specific about which items of public spending should be cut than either of the two main parties. As Danny Alexander, the MP for Inverness who is Mr Clegg's "chief of staff", said when he mocked the Tory leader's plan to end subsidised food at the House of Commons: "The Liberal Democrats have proposed not renewing Trident; David Cameron wants to increase the price of salads."

A decision to give up Britain's nuclear deterrent – if that is what Mr Clegg proposes (he has left himself a little wriggle room) – is not one to be taken lightly. But it can no longer be dismissed as mere oppositional posturing. Such is the appalling state of the public finances that those in the two main parties who want to renew Trident are obliged to spell out how they would save an equivalent amount of money – or how they would raise the same amount in taxes.

Not all of the Lib Dems' fiscal proposals are watertight. Mr Cable was caught out last week on the differences between a pamphlet he has written and official party policy. But they are far ahead of Mr Cameron, who is in turn some way ahead of Gordon Brown, who only reluctantly brought himself even to use the word "cuts" last week.

If honesty about spending cuts is hard enough, only Mr Cable, who is interviewed by our political editor on page 27, is willing to speak plainly about the need for tax rises. Mr Cameron and Mr Brown are equally in denial about that salient feature of the political landscape of the next parliament.

Nor is this Liberal Democrat straight-talking a pose adopted safe in the knowledge that the party would never have to take responsibility for it. We know that a hung parliament has been predicted at every general election since 1974, but the next election really does offer the greatest chance of an inconclusive outcome since at least 1992. If there is to be an emergency Budget soon after the election, in a situation where no party has a majority, it may well depend on Liberal Democrat votes.

On other important issues that will face a new government, the Lib Dems have adopted positions at the leading edge of realism. Mr Clegg, advised by Lord Ashdown, the grand old man of modern liberalism, has asked the hard questions about the Nato mission in Afghanistan, and Britain's part in it, that Labour and Tory leaders slide round. On civil liberties, strong Lib Dem representation in a hung parliament should either buttress Tory liberalism, which often seems opportunist, or dilute Labour's authoritarianism.

Above all, The Independent on Sunday believes that the Liberal Democrats are the most environmentally friendly of the three main parties. Indeed, this weekend the party is making a bold pitch that it is the real Green party. Mr Clegg launches a direct appeal on page 37 to anyone who is thinking about voting for the Greens to "lend your vote to the Liberal Democrats in 2010, to stop climate change". It is a powerful argument: that the time has come for those that care about environmental sustainability to do more than use their vote to "send a message"; that, at this election, the Liberal Democrats are the greenest party with a realistic prospect of gaining a share of power. Mr Clegg claims that a Green vote is a wasted vote. Well, that is certainly untrue in Brighton Pavilion, where Caroline Lucas, the Green Party leader, is standing. And it is an impertinence for a Liberal Democrat to use the "wasted vote" line against an even smaller party.

But, this week of all weeks, the Liberal Democrats' arguments on the environment, on the economy, on civil liberties and on a liberal internationalism deserve to be heard.