Leading article: On your marks, please, Sir Menzies

In the general election only last year, this newspaper advocated intelligent voting "to promote the values of environmental sustainability, social justice, human rights and the rule of international law". We concluded that this meant voting - where they could win - for the Liberal Democrats. The party increased its number of MPs from 52 to 62, and has proved remarkably resilient since. The Conservatives have launched a sustained and - at last - clever attempt to invade their green and civil libertarian territories. The Lib Dems have replaced a leader who was popular but flawed with one who merely lacks lustre. Yet the party's support among the voters is consistent at around 20 per cent. That is a substantial body of support that offers the solid hope that the Lib Dems will have a part to play in government - with the next election their best prospect for a quarter of a century.

It is a pity therefore that Sir Menzies Campbell is not enough of an opportunist - because he, more than the other two national party leaders, has to take his chances in the media as they present themselves.

It is a pity, too, that this week's Lib Dem conference in Brighton - the party's one reliable chance to write its own headlines - is likely to be dominated by mooning over Charles Kennedy's personal demons and arguing over a 50p-in-the-pound rate of tax on high incomes. As it happens, this newspaper shares the view of Shirley Williams, who supports the policy. But it is not a priority. It is far more important to raise taxes on those who consume too many of the planet's resources than it is to raise taxes on the rich - especially when, broadly speaking, they (or we) are the same people. This Labour Government has made important if limited progress towards social justice but has failed miserably to reduce the carbon emissions that are responsible for climate change.

Meanwhile Sir Menzies has allowed David Cameron to overtake him on the bend with green gestures and green postures that have not yet been tested by the doping authorities. The Liberal Democrats ought to be setting the pace in the race to save the planet, but so far Sir Menzies looks as if he is merely limbering up.