Sneering is easy but Sir Bob deserves applause

When Tony Blair first suggested that he was thinking of making Africa and climate change the priorities of Britain's presidency of the G8 group of rich nations, it is all too easy to imagine the Yes, Prime Minister moment that followed. "What interesting ideas, Prime Minister," Sir Humphrey would have said. "How very brave." As life imitated art, civil servants then offered Mr Blair some lower-risk alternative priorities that would be more likely to produce what are known in New Labour jargon as easy wins. It is to the Prime Minister's credit that he rejected their advice.

When Tony Blair first suggested that he was thinking of making Africa and climate change the priorities of Britain's presidency of the G8 group of rich nations, it is all too easy to imagine the Yes, Prime Minister moment that followed. "What interesting ideas, Prime Minister," Sir Humphrey would have said. "How very brave." As life imitated art, civil servants then offered Mr Blair some lower-risk alternative priorities that would be more likely to produce what are known in New Labour jargon as easy wins. It is to the Prime Minister's credit that he rejected their advice.

We applaud the same spirit of attempting the impossible in Bob Geldof. His aggressive piety can be irritating; his wilfulness can be irresponsible. His call for a million people to march on the G8 summit at Gleneagles next month was literally asking for trouble. But as a call to moral arms, we know what he meant.

It is always easy to cavil, to sneer at idealism, to point out that Mr Blair's high rhetoric has been used as a cover for low politics before, or that Mr Geldof's consciousness-raising efforts have produced limited or ambiguous results. It is easy to dismiss the motives of rich celebrities wearing white wristbands (which we analyse on pages 14 and 15). Above all, it is easy for those who broadly agree on the objectives to disagree about the policies for achieving them. It should be recognised that, in their approach to poverty in Africa and elsewhere, Mr Geldof, Mr Blair and Gordon Brown are all essentially on the same side. It is even possible to recognise that George Bush has done some good in Africa, such as putting resources into Aids treatment.

Effective idealism is not a matter of absolutes: it is a process. Mr Geldof is a prime example. His raw anger at the needless suffering in Ethiopia that inspired Live Aid 20 years ago has matured into the more considered manifesto of the Africa Commission, on which Mr Geldof sat and which reported earlier this year. From the naivety of "Just give them the money" he has moved to an understanding of the need to support good governance and free trade - which is, after all, what "fair" trade really means.

In the parallel struggle to secure effective action against global warming, a similar pragmatism is required. It is no use simply railing against energy-hungry America, or the obstinacy of Mr Bush, however wrong-headed he might be. Mr Blair is pursuing the right tactic in lobbying swing members of the US Senate, of working with the growing elements of the US polity that recognise the dangers of climate change.

These are causes that inspire idealism and a sometimes strident demand for instant action. The true idealist recognises that the problems of Africa and of climate change are not amenable to easy solutions, and that progress will often be frustratingly slow, if not impossible. But that is what makes it worth attempting.