Alameda Park is Mexico City's languid space for lovers and open-air ballroom dancers: the gents in two-tone shoes, the ladies in finery and heels. The cobbled paths undulate from the great earthquake of 1985. You imagine the fairground sinking into the cobwebs of cracks, its Edwardian organ playing forlornly. Two small churches nearby totter precariously: the surreal is Mexico's facade.
Hidden behind the poplars is the museum where Diego Riviera's mural Dream of a Sunday Afternoon in Alameda Park occupies the entire ground floor. You sink into sofa chairs and journey for an hour across his masterpiece. Originally painted at the Hotel Prado in 1947, it was rescued and restored when the earthquake demolished all around. More than 45 feet long and 14 feet high, it presents the political warriors of Mexico's past, from the conquistador Hernando Cortes to Rivera himself, depicted as a child holding the hand of a fashionably dressed skeleton, the iconic symbol of the Day of the Dead. Standing maternally beside him is his wife, Frida Kahlo, Mexico's artistic heroine. Around them parade the impervious rich and unrequited poor.
What is it about Mexico that is a universal political dream? As in a Rivera mural, nothing is held back: no class martyrdom, no colonial tragedy. The message is freedom next time. The autocracy that emerged from the revolution of 1910-19 gave itself the Orwellian-name Party of the Institutionalised Revolution. This was eventually replaced by businessmen promising a pseudo democracy, which in 1994 embraced Bill Clinton's rapacious North American Free Trade Association (Nafta). Within a year, a million jobs were destroyed south of the border, along with Emiliano Zapata's revolutionary triumph, the constitutional protection of indigenous land from sale or privatisation. At a stroke, Mexico surrendered its economy to Wall Street.
The beneficiaries of the new, privatised Mexico are those like Carlos Slim, now ahead of Bill Gates as the world's richest man, whose fingers are lodged in every imaginable pie: from food and construction to the national telephone company. A US diplomatic cable released by WikiLeaks says, "The net worth of the 10 richest people of Mexico – a country where more than 40 per cent of the population lives in poverty – represents roughly 10 per cent of the gross domestic product."
The last election, in 2006, was won by Felipe Calderon, Washington's man, followed by persistent allegations that it was rigged. Calderon declared what he calls "a war on drug gangs" and 50,000 dead are the result. No one doubts the menace of the drug cartels, but the real "security issue" is more likely the resistance of ordinary Mexicans to an enduring inequity and a rotten elite.
For most of this year, thousands of los indignados have taken over the massive parade ground known as the Zocalo facing the National Palace. The occupations in Wall Street and around the world have their genesis in Latin America. The difference here is there is none of the angst about the protestors' "focus". As in all places where people live on the edge and the state and its cronyism cast lawless shadows, they know exactly what they want. Ask some of the 44,000 employees of the national power company, who prevented the fire sale of the national grid until Calderon sacked them all; and the striking copper miners of Cananea, whose owners funded Calderon's campaign; and the former pilots and stewards of the national airline, Mexicana, dissolved in a sham bankruptcy that was a gift to the private airline industry.
These angry, eloquent and often courageous people have long known something many in Europe and the United States are only beginning to realise: there is no choice but to fight the economic extremism unleashed in Washington and London a generation ago. Employment, trade unionism, public health, education, "life itself", says Manuel Lopez Obrador, the former mayor of Mexico City who ran against Calderon, "has since been struck by a political and economic earthquake". Since Calderon came to power, 30 journalists have been killed, ten this year alone, says the Committee to Protect Journalists. Again, the drug cartels are blamed, but suppression of a national resistance, co-ordinated with the United States, is also the truth.
Unlike in the US and Britain, many journalists, some of them inspired by the rise of the Zapatistas in the 1990s, have thrown off the patronage of the political and business elite and pursue what they call "civic journalism". The second largest newspaper in Mexico is La Jornada, famous for its fearless investigations and campaigns and for surviving mostly on subscriptions; it carries no commercial advertising. Reminiscent of newspapers before they were consumed by corporations, there is nothing like it in Britain; it reflects much about Mexico City that is surprising and enlightened.
In the National Palace the presence of Robocop guards is at once overwhelmed by Diego Rivera's most epic mural. Painted between 1929 and 1945, it follows the walls of the staircase, spilling, like his Alameda work, spectacles of revolution and tragedy, hope and defiance. When I filmed it 30 years ago, I tried unsuccessfully to write a narrative to the pictures. In condensing and bringing alive 2000 years of history, it is art of which Europeans and North Americans are sometimes disdainful yet envious; for it charts the struggle of ordinary people, uniting and celebrating them, and identifying their true political enemies. Seeing it again, I am struck by how it speaks for us all.
On 1 November, John Pilger was awarded Britain's highest honour for documentary film-making by the Grierson Trustees, in memory of the documentary pioneer John Grierson.