Picture a man who is patiently and quietly enduring a rather painful medical procedure. Standing beside his bed is a bronzed and healthy character in a shiny suit who shrieks "Ouch! Aargh! Oh my God! I can't take any more of this!" as the knife goes into the other man's body. That first man is Britain today, stoically facing another round of terrorist attacks and the inconvenient security measures they have provoked. The hysterical bystander is American television's Fox News, whose reports from in front of an airport terminal in Glasgow or a street-corner in London are presented as if they were bulletins from the Normandy beaches or the Burmese jungle during the second world war. For this is the fourth world war, isn't it?
No, actually, it isn't. That's the big mistake you're making, Mr Fox. And you, Mr Bush. The London and Glasgow attacks remind us once again that we face - in Britain probably even more than in the United States - a serious threat from international jihadist terrorism, smaller in scale but harder to anticipate than that from any conventional army. Yet one thing that has impressed me, as I watch from very far away, is how the British government has again kept its cool, insisting, even at the height of critical security alert, that we continue with business as usual, maintain a sense of proportion and recognise that there are still other challenges in the world. And some of them may even be bigger.
It's interesting to follow these events from a country, indeed, from a continent, which has virtually no threat from Islamist terrorism. To talk here in Brazil about Europe's homegrown jihadists is rather as I imagine it would be to lecture in Brixton on the Yanomami people of Venezuela and Brazil. But Brazil has other problems - and some of them are our problems too. I am in the southerly city of Porto Alegre. Guardian readers, being a formidably well-informed lot, will immediately recognise Porto Alegre as the birthplace of the World Social Forum (WSF), conceived as an alternative to the World Economic Forum in Davos. "Porto Alegre" says global south versus north, poor versus rich, anti- or alternative-globalisers versus ruthless capitalist globalisation - and, if you will, Porto Alegre woman versus Samuel Huntington's "Davos man".
Porto Alegre woman herself turns out to have a healthy scepticism about this global branding. When I asked a senior official of the city council for her view of the WSF, she said "it was good for the hotels in the low season". (The forum, which is now hosted by different cities around the world, used to take place at the height of the Brazilian summer, when most Porto Alegrans had decamped to the seaside or the hills.) It was a happening, commented another Porto Alegran, describing the camps of young international activists as a kind of Woodstock. My guidebook told me there was an informative exhibition about the forum in the city museum. I went there and talked to the director. "It's gone," he said. The whole idea was so closely associated with President Lula's Labour party that when they lost control of the city government, the exhibition disappeared.
Here, as in Rio and Sao Paolo, I have heard some sharp criticism of President Lula's approach to foreign policy, because it identifies Brazil too exclusively with the concerns of the south, aligning the country only horizontally, so to speak, with other developing countries and members of what used to be called the third world. Brazil is also part of the west, say these critics, pointing both to the country's cultural heritage and to its democratic institutions. Parts of its cities, including Porto Alegre, look very like the rich north. Brazil has, after all, the eighth largest economy in the world. The country even has a dash of the far east, with the largest Japanese population outside Japan. Not to mention the Middle East: there are at least 7 million Brazilians of Lebanese descent, roughly double the number living in Lebanon itself.
That said, the central priority of Brazilian foreign policy remains, and must surely remain for some time to come, the country's own economic and social development. Yet even from that starting point, it ends up bringing to the global agenda a set of issues which have nothing to do with the war on terror, but which none the less have large implications for us all. The poverty, inequality and criminality that I wrote about last week are a product of Brazil's own history; but they also have some current external causes. The agricultural protectionism of Europe and the United States, for example, is a major obstacle to Brazil's more rapid development. On free trade, we in the rich north do not practise what we preach. As a result, we are responsible for keeping some of Brazil's poor in poverty. That is the issue rightly posed by the G20 group of developing countries, in which Brazil plays a leading part, during the Doha round of trade talks.
Or take the environment. What Brazil does with its rainforests will directly affect the prospects for global warming, and therefore our future climate. But restraint carries a price for the local population. Meanwhile, as an emerging economy, the country's own carbon dioxide emissions are growing fast. I spoke here with a leading Green party member of the Brazilian parliament, who argues convincingly that Brazil should lead the way for India and China in setting voluntary target limits. But what will we, in the rich north, do for Brazil in return?
I'm not arguing that these issues are necessarily more important than the challenge of international jihadist terrorism. I'm not sure how you would rank them. I am simply arguing that they are vital too. Nor is it a case any more of: "Well, you have your problems and we have ours. Let's each look to our backyard." The ties of global interdependence are already too tight. So we need to keep addressing all these major challenges at the same time.
This is what Washington is so chronically bad at. One American president, Lyndon Baines Johnson, is reputed to have said of another, Gerald Ford, that he couldn't fart and chew gum at the same time. Not that the nation's capital is too dumb. Not that it doesn't have the relevant expertise - you can find better experts in Washington on most areas than you can in London, Paris or Beijing. But the United States' media-led political process allows for only one major focus at any time.
The true message of Porto Alegre is not that we have to turn to a wholly different agenda of world politics. It's not a case of the social versus the economic, the environmental against the military, either Porto Alegre or Davos: tick only one box. Rather, it is the need for multi-tasking in global democratic leadership. And to bring that about, we need a broader community of democracies, in which countries such as Brazil, India or South Africa take their place alongside the established democracies of the old west, acting in coalitions of the willing in those areas where they have something to contribute. Since the United States seems currently incapable of taking the lead in that direction, perhaps Gordon Brown's new government should make this its foreign policy signature tune.
Timothy Garton Ash