The Lib Dems are caught between leftist instincts and rightist needs

It didn't take long. Towards the end of his question and answer session yesterday in Brighton, and less than 72 hours after the victory of Brent North, Charles Kennedy was asked whether he thought his party would be celebrating the centenary of the momentous 1906 Liberal landslide having won a similar general election victory. Mr Kennedy, to his credit, was admirably restrained. He said, in a masterpiece of understatement, that such speculation might be "premature", but added that politics was a buyer's market and that there were big opportunities "out there".

Of that, of course, no Liberal Democrat delegate is any longer in doubt. A few moments later, at a packed fringe meeting, David Laws, a leading intellectual driver of the party and as hard-headed a man as you're likely to encounter here, issued a timely warning against "over-interpretation" of the Brent result. But then even he went on to say that the by-election might turn out in hindsight to have been the "high water mark" not only of Iain Duncan Smith's Tory leadership but of the Blair premiership itself.

In this heady atmosphere, and perhaps even beyond its reach, it isn't hard to believe there may be something in this. What will now preoccupy the Liberal Democrats - rightly - is firstly how great those opportunities really are, and secondly how best to exploit them. On the first question, an emerging theme in Brighton (touched on by Mr Laws yesterday) is the growing disappointment of elements of the coalition that it was Tony Blair's unique achievement to assemble on 1 May 1997. No element, of course, is entitled to be more disappointed than the Liberal Democrats themselves. Having conspired informally with Labour to maximise the tactical voting which helped to see off the Tories in 1997, the party was then seduced into a continued and now abandoned compliance by a series of half-promises which have one by one evaporated into the mist: Commons electoral reform, a euro referendum, democratising the Lords.

It's that which has helped to turn the Liberal Democrats into an opposition party; and it's what reinforces its claim, in the absence of a credible Tory party, to voice that wider disappointment, much of which crystallised over the issue of war in Iraq. At the same meeting yesterday, Nick Clegg, one of the brightest of the new Lib Dem parliamentary candidates, characterised Tony Blair as an old-fashioned Christian Democrat, a top-down authoritarian and obsessed with his relationship with the US President. This may be a caricature. But it helps to encapsulate the potential Lib Dem appeal to the parts of the coalition that now threaten to peel off: liberal in every sense, anti-authoritarian, truly devolving and localising, pro-European.

On the second question - how best to position itself in the wake of Brent - the party remains, to appropriate a phrase of Baronness Williams of Crosby yesterday, "fuzzy". Even as the party's leaders decry left-right labels as political oldspeak, the barely submerged internal debate here is precisely over whether post-Brent the Liberal Democrats should be/are to the left of Labour or not. Part of all this, of course, is a mere matter of cold electoral strategy. A seductive reading of the developing landscape is that the fact that four-fifths of the party's target seats are Tory-held need not deter it from fighting them from a position to the left of Labour. The way to win those seats, it can be argued, is to squeeze the Labour vote, and what better way of doing this than to be more Labour than Labour itself?

Against the background of such an analysis, the attempt by the Health spokesman, Evan Harris, to commit the party to a bonfire of prescription and other health service charges and replace them with taxation makes perfect sense. Mr Harris, it seems, won't get the hard and fast commitment he wants. But his bid to re-fight the battle the Bevanites lost in the Labour Party in 1951 taps into a vein of support from party activists which has been enriched by the dramatic Lab to Lib swing at Brent.

Today, by contrast, Vincent Cable, the capable Trade and Industry spokesman, will deliver a deregulatory, free-market, free-trade message. Mr Cable is seeking to encapsulate the argument also enunciated by Mr Laws yesterday - that economic liberalism matters as well as social liberalism. And that too is underpinned by a psephological reading - that the Lib Dems cannot realise the advances it now hopes for without eating into at least some soft Tory votes, let alone consolidate its grip on seats where the direct challenge is to hold or win what was once Tory support: Winchester, Newbury, Christchurch, Guildford, and so on.

Nowhere is this difference more salient than on tax. The Treasury spokesman, Matthew Taylor, will make clear today that in proposing a local income tax to replace the increasingly unpopular council tax, he does not envisage a rise in the overall tax burden. Some in the party would go further, arguing that to underline its fiscal prudence as well as dramatise the shift from national to local taxation (necessary if the party is to make sense of its commendable commitment to more local control, and therefore variation, in the delivery of public services) the party should announce a headline cut in nationally collected direct taxes.

Why should any of this matter? Even on the most optimistic reading, the Lib Dems are not going to supplant the Tories overnight, let alone form a government. But on present showing it isn't outlandish to suppose that they might go from 54 to 80 or more seats in the next general election. It could threaten a clutch of Labour constituencies in Watford, Islington South, Birmingham Northfield, even Charles Clarke's in Norwich South, as well as its Tory targets. It could "decapitate" the Tory party by taking out some if its stars: David Davis, Theresa May, Oliver Letwin, even Michael Howard. And the inevitable result, as Charles Kennedy well knows, is that the party is going to be subjected to unprecedented scrutiny - and vilification by its opponents - from now on in.

Which means in turn that economic credibility suddenly matters as never before. Which is why the Cable/Laws argument is a necessary adjunct of what should now be an unbridled attack on New Labour's authoritarianism, uncritical alignment with a Republican US President, and the emptiness of its promises of a new pluralist reinvigoration of democracy. This doesn't mean warmed-up Reaganomics; far from it. If it did, the Lib Dems wouldn't be opposing tuition fees or pursuing free nursing care for the elderly. But it's a price of the party's remarkable success that it can't be fuzzy any more. The attacks from the other two main parties may seem pretty empty just now. In the run-up to a general election they may not be. The Liberal Democrat opportunity remains to be truly liberal in every sense; if it can achieve just that, the Conservatives have every reason for fear and little for hope.

d.macintyre@independent.co.uk