Leading article: Modest success, serious challenges

Liberal Democrats assemble in Birmingham this weekend in better heart than could have been expected, after all they have been through over the past 16 months. Since the election, this newspaper has disagreed with Mr Clegg's change of mind about a graduate tax; we have been puzzled by the Liberal Democrats' claim to have improved Andrew Lansley's NHS changes; and we have been impressed by Chris Huhne as Climate Change Secretary. But it is hard to identify definite Lib Dem achievements that would not have happened anyway.

The one thing that David Cameron would certainly not have done was to hold a referendum on changing the voting system. It was hardly Mr Clegg's fault that the result went against what The Independent on Sunday wanted, but it was not much of an achievement either.

The Liberal Democrats have had limited successes, in raising the income tax threshold to take some of the low-paid out of the tax system, and in blocking reactionary Conservative ideas such as a tax break for marriage and rolling back the Human Rights Act. Yet all those dire predictions that Mr Clegg would be unable to hold the two wings of his party together have turned out to be, if not wrong, at least premature. Mr Huhne's comment last week that Mr Clegg would be a "tremendous" European commissioner – a post coming vacant in 2015 – was mischievous but hardly amounted to a leadership challenge.

In part, this reflects the party's sincerity about the virtues of working with other parties, and its experience of doing so on local councils. This means having the confidence to alienate one group of supporters by forming a coalition, in the belief that, over a parliamentary term, the junior partner's influence will bear fruit.

It must be said that our ComRes opinion poll today lends little support to this view, with only 23 per cent of people agreeing that the Lib Dems have "done a good job of moderating Conservative policies", and only 24 per cent that the experience has shown them to be a "credible party of government".

Danny Alexander, the Chief Secretary to the Treasury, makes a good attempt in his interview on pages 12-13 to sound as if he really will get tough on tax avoidance and evasion by the rich, although we cannot help but notice that he promised something similar last year. The Liberal Democrats ought to be particularly sensitive to our poll finding that only 27 per cent of people accept that coalition policies ensure we are "all in it together". But Mr Alexander's plan feels suspiciously like a well-timed public relations announcement rather than the start of a real crusade for social justice.

Still, we are prepared to give the Liberal Democrats the benefit of the doubt. There is a dynamic about the coalition, a form of government not seen at Westminster in peacetime since 1935, that should mean that Liberal-Democrat values, if they are strong enough, are transmitted throughout the Whitehall machine. Now Mr Clegg and his colleagues need to prove themselves in the following areas.

First, on the economy, we hope that, as George Osborne revises his plans in the light of gloomier forecasts from the Office for Budget Responsibility, Mr Clegg, Mr Alexander and Vince Cable, the Business Secretary, successfully make the case for more Keynesian stimulus rather than less.

Second, on fairness, the party must follow up on Mr Alexander's attempt to force the rich to accept their share of the fiscal burden.

Third, on the environment, holding Mr Cameron to his pledge to lead the "greenest government ever" at a time of austerity would be a great achievement.

If there were a fourth area, it would be our relations with the rest of Europe, which matters in dealing with everything else. The economic crisis is now plainly a crisis of European governance, in that, as the Prime Minister and the Chancellor say, a disorderly break-up of the euro would be bad for Britain. Yet there are elements in the Conservative Party whose stop-the-EU-we-want-to-get-off isolationism would be profoundly damaging to the national interest. We need a constructive attitude to our European partners for everything from green policies to attempts to reform the European Court of Human Rights.

That is how the Liberal Demo-crats can still make a positive difference in the next three and a half years of the Government's legislated span, and those are the policies on which the party conference should focus this week.