RETURNING FROM the World Social Forum (WSF) at Porto Alegre in Brazil, I feel as if I have just emerged from a vast, multicoloured sea that swept all the participants along in a great exuberant wave.
The figures, to begin with, are amazing. There were 100,000 participants (twice as many as last year), including 20,763 delegates representing 717 organisations from 156 countries, who attended 1,286 workshops and other bigger events. The Gigantinho Stadium, capacity 15,000, was the venue of a series of packed meetings throughout the forum.
To be there when it was full of young Latin Americans cheering two English-speaking anti-war activists - Arundhati Roy and Noam Chomsky - to the rafters was to witness the development of a new internationalism. Even as experienced a speaker and activist as Tariq Ali told me that he was overwhelmed when he got a similar reception at the Gigantinho.
On the demonstrations that opened and closed the forum the small but noisy European anti-war contingent - mainly from Britain and Italy - was able to attract many young Brazilians who liked its dynamism and its focus on opposition to Bush's war drive.
George Monbiot was quite right when he wrote in the Guardian last week, 'Far from dying away, our movement has grown bigger than most of us could have guessed.' Even the extreme right wing of European social democracy has woken up to the significance of the anti-capitalist movement that has stretched across the globe.
Last week's New Statesman carried a piece on the WSF by Edward Miliband, a special adviser to Gordon Brown. He acknowledged that 'despite their determination to stick to the politics of protest, not the politics of power, those gathered at Porto Alegre do represent a challenge and a lesson' to the mainstream centre-left.
Some people inside the movement are worried about the attention we are now getting from the governmental left. Naomi Klein in last Saturday's Guardian complained about the prominence at Porto Alegre of 'big men'.
She specifically referred to the newly elected Brazilian president, Lula, and Venezuelan president Hugo Chavez, both of who addressed big rallies during the WSF. Klein asked, 'How on earth did a gathering that was supposed to be a showcase for new grassroots movements become a celebration of men with a penchant for three-hour speeches about smashing the oligarchy?'
The answer is simple - most people who attended the forum support Lula and Chavez. As leader of the Workers Party, Lula is seen as the embodiment of the Brazilian workers' and landless labourers' movements that are two of the main forces behind the WSF.
Hugo Chavez is widely supported throughout Latin America as a symbol of the reviving resistance to US imperialism that is sweeping through the continent. It is easy enough to pick holes in the politics of both men. Lula is signed up to a neo-liberal economic programme that will make it impossible for him to fulfil the hopes of his supporters.
Chavez is in many ways a familiar Latin American figure - a radical nationalist military leader who is encouraging mass mobilisation against the right because he has to rather than because he wants to. State Nevertheless, the mass support that both men enjoy is a fact that more radical anti-capitalists cannot ignore.
Klein complains, 'Two years ago, at the first World Social Forum, the key word was not 'big' but 'new': new ideas, new methods, new faces.' And it's quite true that there is much that is new about the anti-capitalist movement - above all, its capacity to organise internationally and the methods of direct democracy that it uses.
There are also old questions facing the movement that it cannot ignore. The most important of these is the state. Klein and many of the people on the autonomist wing of the movement see the state as something that can simply be bypassed.
Changing the World Without Taking Power is the name of an influential book that sums up this approach - let's not worry about the state but just concentrate on building local and global networks that outflank it. The past two years have shown the inadequacy of this approach.
We've seen the domestic face of state violence unleashed against demonstrators at Genoa and in Argentina, and its external face in the Bush-Blair war drive. Lula and Chavez represent the wing of the movement that believe we can use the existing state.
They are wrong, but they are at least addressing a question that people like Klein evade. If we want to draw their supporters towards more radical approaches, then we are going to have to come up with a better answer to the problem of state power.