This is becoming quite a week. It began on Saturday, with vast numbers of people around the world demonstrating an idealism and a generosity regardless of national interests, and challenging the world's most powerful countries to do the same.
Mr Bush says he will do what is best for the US
It will continue at Gleneagles in Scotland on Wednesday, when the leaders of those countries meet at the G8 summit.
Most of the world's most urgent problems, from world poverty and the manifest unfairness of international trade to the overpowering threat of climate change, are on the agenda.
And, like some strange planetary conjunction, the announcement of the 2012 Olympics will be made on Wednesday, just as the G8 meeting is starting.
Some British officials are nervous that if London beats Paris, President Jacques Chirac of France will be in wrecking mood at Gleneagles; though that seems a little unlikely.
I hate to say it, but all the evidence of past summits like this, and I have been covering them since they started in the 1970s, is that the results never match the expectation.
This time, though, things are a little different. UK Prime Minister Tony Blair, anxious to try to rebuild some of the trust he has lost at home, has formed an ad hoc alliance with Live 8 organiser Bob Geldof to infuse some idealism into the G8 process.
Live 8 ambush
As a result, they have staged a kind of ambush for the other G8 leaders: fulfil the expectations of the millions who watched the Live 8 concerts around the world, they are saying, or be condemned as failures.
The trouble is, self-interest is always the dominant force at these summits: like it or not, that is the way of the world.
Some G8 countries - Germany, Italy and Canada, in particular - resent being railroaded into giving more aid to poorer countries, and particularly to Africa, which Mr Blair and his powerful Chancellor of the Exchequer Gordon Brown, have placed at the heart of this summit.
But there are even more important fault lines. Most, if not quite all, the other leaders strongly resent President George W Bush's resistance to the Kyoto Agreement, and they will not have been altogether impressed by the concession he made in his interview with Britain's ITV News.
In most parts of the developed world, global warming is now seen as the most pressing threat to mankind. So merely conceding that it is something "we've got to deal with", and accepting that human activity is "to some extent" to blame, is going to irritate more people than it appeases.
And for Mr Bush to suggest that new technologies are the way to deal with the problem, rather than cutting the emissions which he now agrees are responsible, will only irritate them more.
Altogether, this is the most contentious G8 summit of recent times. Behind the smiles and the hearty handshakes, there will be a great deal of residual anger.
The wounds originally opened up by Mr Bush's invasion of Iraq have never entirely healed, and the resentment against the US for believing it was powerful enough to do without international support has never entirely gone away.
Yet France and Germany are more angry with Mr Blair than they are with Mr Bush; and Mr Bush showed in his ITV interview that he is not planning to do his friend Tony any favours at Gleneagles.
The Gleneagles hotel will host the G8 summit
"I go to the G8 not really trying to make him look bad or good," Mr Bush said, "but I go to the G8 with an agenda that I think is best for our country."
It was not very diplomatic, considering how Mr Blair put his neck on the block for him.
Still, Mr Blair can look after himself. He will not want Mr Bush to be isolated or humiliated, but he will want it to be clear who is responsible if there is no substantive deal over global warming.
And he wants US help in his new crusade against the European Union's common agricultural policy. There, at least, Mr Bush was prepared to be forthcoming.
He indicated he would be prepared to abandon the huge subsidies to American farmers if the Europeans scrapped the Common Agricultural Policy (CAP).
Of course he knows the CAP will never be entirely scrapped, and that anyway he will no longer be president if it is. But it sounded good.
Sounding good, or trying to, is about the best that will come out of this summit. Like the doubling of America's aid to Africa, like the relief of debt for the poorest countries, these things are at their most impressive when expressed in headline terms.
When you realise that American aid is still well below the internationally recommended level, and that large numbers of deserving countries are still excluded from debt relief, the phrases sound less fine.
If the agreement on aid for Africa is clearly generous; if the statement on tackling global warming is outspoken and unambiguous; if there is a real undertaking to do something serious about the grotesquely selfish agricultural subsides which American and European farmers receive; then the Gleneagles summit will deserve to stand alongside the Marshall Plan for far-sighted, open-handed self-interest.
But I'm not holding my breath.
When is a subsidy a bad thing or a good thing? The CAP means that in some cases local goods in Africa are undercut in price by EU goods. On the other hand subsidies to banana growers in the Windward Islands helps their economy, something I think that the EU wants to do away with or already has done. A radical rethink is needed, since food is something we all need. However, who could be independent in allowing subsidies in one area but not in another? That's an onerous task for anyone.
John Airey, Peterborough, UK
I entirely agree with Mr Simpson. All G8 nations will attempt to stand their own ground on what they perceive are their own important issues. It still troubles me however, after commencing work in Africa in 1981 (Angola) and (Congo) (Zaire) recently (2003) working in Chad, I saw absolutely no difference in the poverty level in 22 years. I am very sorry to say I find it hard to believe things will be any better in 22 years from now.
Richard Bull, Lincoln, UK
I'm likewise expecting headline grabbing but empty promises from G8. Unfortunately, too much relies on Bush. He is self-obsessed with self interest, and has surrounded himself with aides who are even more self-obsessed with US matters than he is. Africa simply will not get what it desperately needs under a Bush administration.
Andy Smith, Pembrokeshire, SW Wales
Some realism at last! John Simpson is right that it will be amazing if anything life changing is decided at the G8. But things look better for Africa than they have for a long time. Let's hope for some progress
Hugh Collins, London, UK
John Simpson is entirely right to point out that narrow self-interest is usually what drives these summits. That was exactly what Saturday's (otherwise rather vague) demonstration was about - the need for the decisions to be taken for the good of all, not just those present. It was, above all, a call for the rich countries to make some difficult decisions which might even hurt a bit, like CAP reform, but which are nonetheless the right thing to do. I sincerely hope they take the opportunity but fear that, since Africans don't vote in the elections of G8 countries, they may not.
Tom Wiltshire, Leeds, UK
Of the three major recommendations for dealing with poverty in Africa, debt relief and the doubling of aid are the easiest. Both are just once-off gestures of generosity and do not address the underlying economic and social problem(s). And since aid has not worked, for the most part, in the last 40 years why should it be doubled? Far more difficult for the G8 will be reaching an agreement to scrap the EU and American farm subsidies and to offer Africa and the rest the world, fair trade relations.
John Molenveld, Windhoek, Namibia