Ever since the leaders of the major industrialised countries met in 1975 to consider the then energy crisis, the meetings of what is now the G8 have been propelled by immediate crises. Try as they might to think calmly about the long-term issues - Africa, inflation, global poverty or whatever - it is always the immediate that has dominated these meetings. Last year it was the 7 July London bombings during the British-hosted summit in Gleneagles. This time it is the Israeli response to the seizure of its soldiers on the borders with Lebanon and Gaza.
Perhaps it is as well. Without an immediate crisis, the G8 - a group originally consisting of the US, the UK, Germany, France, Italy and Japan and since broadened to take in first Canada and now Russia - would be an anomaly, a club of major economies of the past now receding in the shadow of the new economies such as China and India. The officials, the sherpas, as they have been dubbed, would spend months preparing a sonorous agenda, but reality would be rather more prosaic - a gathering of largely Western premiers intent on claiming a few headlines back home but unable and largely uninterested in shaping events together.
So it might have been on this occasion. The formal agenda as set by the hosts - the Russians chairing their first summit in St Petersburg - was intended to concentrate on energy security in the face of escalating oil prices and growing concern over supply. It was meant to confirm Russia's status not only as an equal partner, post the collapse of communism, with the US and Europe, but also its strength as a major supplier of oil and gas.
In that sense, the summit has already been a success for its hosts before it has even begun. Despite all the concerns that Russia was not democratic enough to be a member of the club, that its economy was not large enough to warrant membership and that its interests were too nationalistic to enable it to act as a constructive colleague, the meeting is going ahead in St Petersburg, kicked off by a private dinner between President Bush and Vladimir Putin.
It's not on Russia's willingness to move to greater democracy, however - important though that is - that the success or failure of this G8 meeting will be judged, but on its response to the wider issues of our time. Global warming, energy shortage, rocketing raw material prices, worldwide terror and now the threat of another Middle East war - all these are crowding in demanding urgent, and concerted, attention.
The G8 is not set up to provide immediate answers. Nor, given the state of division between some of the players and the woeful failures of Europe, can one expect much co-ordinated effort. But the summit at St Petersburg does provide a venue for informal exchanges between leaders and a platform for agreed positions at the end.
At the very least, the leaders attending - and they include four of the five permanent members of the Security Council, including Russia - should issue a firm statement on the Middle East demanding that all the combatants accept a ceasefire and withdraw behind their borders and promising full international support to peace talks. At the minimum they could also affirm their belief in measures to reduce global warming and to increase energy supply. Russia must not be allowed to get away with a policy that enforces a monopoly of fuel production at home while insisting on its right to buy into the outlets abroad.
Of course, summits such as St Petersburg are talking shops. But this time there is a lot to talk about and the presidents, prime ministers and chancellors attending owe it to the wider public to talk hard and hammer out a serious and constructive communiqué at the end.