The most effective political slogans are often the shortest. Perhaps the best campaign motto in the United States came in the 1946 mid-term ballot. It was coined by the Republicans against a backdrop in which the Democrats had controlled Congress for 15 years and where the deprivations linked with wartime had continued long after victory was secured.

It contained a mere two words, within them a double-entendre. The message? “Had enough?”. Voters decided that they had indeed had enough of the Democrats, but not enough of life’s little luxuries. The Republicans duly swept the board.

The two words that haunt the Liberal Democrats are different, yet they are casting a shadow over their leadership contest and they will define the task for whoever wins. The words are, “Who cares?” Possibly, it is the most devastating question that could ever be put to a political party.

A lot of not only the cynical punditocracy but also the public wonders why it should be bothered with the Liberal Democrats at the moment. To lose one leader in inauspicious circumstances is pretty bad. For another to decide a meagre 19 months after being chosen that he didn’t have enough support among his colleagues to continue is more devastating still. Trouble at the top is, though, the least of the party’s difficulties. Its opinion poll ratings have been very fragile for the greater part of two years. The election results for the Scottish Parliament and Welsh Assembly in May were deeply disappointing.

Things have been in many ways worse than dire. Serious people are asking if there is any point to the Liberal Democrats and to liberalism. Should not the more left-wing of their MPs split and join Labour while those on the right simply align with the Tories – as happened for much of the 20th century. Is this not less a coherent organisation than a collection of middle-class do-gooders? What prospect of any worth does this amiable but eccentric lot have at the election anyway?

Such sentiments are understandable but unreasonable. What might look like an intellectual and political crisis for liberalism is greatly overstated. If the standard to be met is, as Nick Clegg has declared, something more than serving as the third party because this is “not good enough”, then the Liberal Democrats may be destined for eternal frustration. By any other yardstick they are not.

The notion that there is no political space for liberalism is a strange one. The Liberal Party and its successors have held firm to similar principles for about 150 years. Their credo includes a staunch belief in individual liberty, a confidence in the capacity of man to improve the chances of all in society, a determination that political individuals and institutions should be constrained by written rules and a dedicated internationalism.

One can see that there are tensions between these tenets and even mock the willingness of Liberals to salute the European Union and the United Nations, despite the manifest failings of those two organisations. Yet only the most harsh would not concede something to the consistency with which they have clung to their cause for so long. It certainly compares well with a Labour Party that is so often social democratic in office but socialist in opposition, or a Conservative Party which has, at different times, been against and for capitalism, for and against free trade, and an advocate, or enemy, of Union and Empire.

Much the same can be said about middle-class do-gooders. They might be a slightly sanctimonious set (cancel that “slightly”) but the list of initiatives and worthwhile reforms with which they are associated is lengthy. If a Martian were to examine the manifestos of the Liberals over the past few decades and then check on the character of life in Britain today, he would not assume that this was a party that last won a majority in the House of Commons 101 years ago. The “battle of ideas” and the “battle for votes” are conducted on very separate territory. That the Liberals have basically failed in the second struggle does not mean that they have been an irrelevance in the first.

Nor are the party’s hopes at the next election as miserable as has been suggested. In recent weeks the standing of the Liberal Democrats in the polls has sunk to 11-13 percentage points, far below their normal level of the past ten years. There is every reason to suspect that this is an artificially low ebb. A new leader will have the chance not only to exploit his own novelty but Labour’s longevity in charge of Westminster and Whitehall, as well as a Conservative hierarchy that has been seduced by the old tunes of crime, tax, Europe and immigration. A target of 20-25 per cent of the electorate is not incredible. A year from here, the party could be in much better political shape.

Yet that will not take place automatically. The fight for the leadership will have an impact. Bizarrely, Mr Clegg and Chris Huhne, his rival, have happily agreed to contend that there is not much of a difference between them. This is inaccurate in terms of strategy. Mr Clegg is more inclined to emphasise the libertarian trait in the Liberal tradition, while Mr Huhne is comfortable with the collectivist outlook. The two would appeal to quite different kinds of voters. This is not a decision about “presentation” alone, as was plain from their first hustings held on Saturday.

The Liberal Democrats have to be less introspective to prosper. They should stick with their principles but, as Mr Clegg is insisting, also be prepared to acquire a more practical streak. There is no shame in being able to enact your own agenda directly. The party has to have a hunger for power, albeit, realistically, as a junior coalition partner. The two words they need to convince the country of are “we matter”.

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