Leading article: Only a real contest will find the right leader

It may seem wise to avoid splits, but muffling debate sits oddly with a party that makes a virtue of its transparency

The political defenestration of Charles Kennedy has shorn the Liberal Democrats of a leader of whom they had come to despair. But it has not rid them of their essential problem, whose roots lie not in Mr Kennedy's drinking habits but in the party's blurred identity and its striving to be all things to all people.

Recent years have concealed these disadvantages from the public, and perhaps from the party itself, which has become accustomed to a life of gain without pain. The past two general elections delivered them a growing number of Commons seats. Under his mandate, as Mr Kennedy never tired of saying, Liberals sat in Parliament in greater force than at any time since Lloyd George's day.

Part of this was down to Mr Kennedy's personality, for the public warmed to a plain-speaking man, seemingly lacking in guile or lawyer-like slipperiness, who cut through cant and what the French call langue de bois - that wooden, élitist style of official discourse that is both impenetrable and sleep-inducing.

But not all the Liberal Democrats' advances can be attributed to Mr Kennedy's strengths. The party also picked up seats because many voters were disillusioned with the two big parties and their leaders, not because they positively identified with the Liberal Democrats, most of whose policies the average member of the public would be hard put to name or describe. Their tactics of fighting general elections s if they were by-elections proved effective in 1997 and 2001. The war in Iraq proved an especial fillip, as the opposition to military intervention against Saddam Hussein cut across the left-right divide in politics, much as the Liberal Democrats do themselves.

Two events brought dark clouds looming over Mr Kennedy's horizon, and neither was to do with his personal life. One was Tony Blair's announcement that he would step down as the Labour leader before the next general election This threatens to bring in a more formidable opponent in Gordon Brown and reduces the impact of the Liberal Democrats' anti-Iraq stance. The other was the arrival of a new Tory leader in David Cameron.

Aside from the fact that the centre ground is now more contested than ever, as the Tories try to outfox them even on green issues, it has become clear that there is no longer any political advantage to be gained from playing a somewhat passive, waiting game, which was Mr Kennedy's style. This is why so many of his lieutenants as well as many of the new MPs in marginal seats became so restive. They wanted to know what banner they are going to be fighting under in the next election, and their now ex-leader didn't offer many clues.

Liberal Democrats now have their work cut out as to where they want to place themselves. Most pertinently, they need to decide whether to take a risk on defining themselves with more clarity.

The temptation in an age of spin, when striking the right tone is said to count for more than articulating policies, may be to fudge the issue. This involves finding a new "unity" candidate, like Mr Kennedy, who is acceptable both to the social democrats and to the party's rightward tilting economic liberals. Hence the swell of support for the elder statesman and now acting leader, Menzies Campbell, who to many Liberal Democrats offers the prospect of a kind of Baldwinesque "safety first".

As the man who, as defence spokesman, led the charge against the Iraq war, Mr Campbell has the advantage of almost guaranteed acceptability to the wider party membership, who rallied as one to that cause. On the debit side, though, he will look old beside Mr Cameron and even beside Gordon Brown, and inevitably will have the image of a caretaker about him.

The second choice would be a leader who belongs more obviously on the left, such as Simon Hughes, or on the right, such as Mark Oaten or David Laws, though it is hard to imagine any candidate of the right happily leading a party whose activists are overwhelmingly centre-left - a point that will work in favour of the Mr Hughes. A final option would be to dish the Tories by skipping a generation and plumping for one of the new MPs, such as Nick Clegg.

As the field now stands, the craving for security almost ensures that MPs will gladly endorse Mr Campbell as their acting leader this week. He will certainly be the safe pair of hands that some of them yearn for.

But if would be unfortunate if, in the name of party unity, important differences were submerged and no other candidate put his or her hat into the ring, thus ensuring that no leadership election even took place. The benefits of an open election have already been seen in the Conservative Party, where a range of candidates have had an opportunity to show themselves, and the country as well as the party has been able to judge their quality as a result.

That would be a real mistake, signifying a desire to postpone the problem rather than resolve it. It may seem wise to avoid potentially damaging splits, but muffling a much-needed debate will sit oddly with a party that makes a virtue of its transparent and democratic character. Indeed, it would make the Liberal Democrats of today look like the Tories of the Macmillan era, which would be absurd.

When the Austrians of the pre-1918 era expressed frustration with their indecisive Habsburg ruler, they would say the emperor needed "to mount his horse", by which they meant stop pointing in all directions, come off the fence, define the main opponent and advance in that direction. The Liberal Democrats need to do likewise, even if a new-found sense of purpose comes at the expense of their old and not quite deserved reputation for being "nice". But none of this necessary clearing of the air can take place without a proper debate, the prerequisite of which is a proper election in which several candidates compete and the party members have the final say.

They are the ones who must then decide what ground they intend the party to occupy and also whether they want a caretaker leader for the duration, or a younger leader for the longer haul. If they opt for the latter, they will have plausible candidates from both wings to choose from, though the advantage of electing a centre-left figure, such Mr Hughes, may be that he is better placed than the standard-bearers of the right to plant the Liberal Democrat flag on political territory that is distinctively their own.