John McCain is desperate to talk about the surge rather than the splurge. His Iraq war is set to cost one trillion dollars, and his deregulation-mania has cost hundreds of billions. So in order to maintain his façade of being "tough on spending", he needs to shift the subject. That's why he has tried to shrink the debate about the Iraq War to one small question. Not: did Saddam have Weapons of Mass Destruction? Not: did Saddam have links to 9/11? Not: why do 70 per cent of Iraqis think the presence of US troops make them less safe and they should go home now?
McCain knows he will lose those arguments, so he wants us to talk solely about whether the surge of US troops last year has been successful. But a hole was just blown in that argument - and blood is rushing through.
Those of us who got Iraq wrong have a particular duty to honestly describe what is happening now. A major study by the distinguished scientific journal Environment and Planning A has just revealed the real picture. The Republican nominee claims the US troops have stopped the violence by their physical presence. To test this, Professor John Agnew and his colleagues used the same techniques the US government has adopted to monitor ethnic-cleansing in Burma and Uganda.
Here's how it works. When an entire ethnic or religious group is driven out, they abandon their houses - and aren't there to switch on the lights. Their areas become much more dark. If satellite images show night-light remains the same in the areas dominated by one ethnic group but significantly falls in mixed areas, you know ethnic cleansing is happening.
So what happened in Iraq? Before, during and after the surge, the areas that had always been Sunni and those that had always been Shia were brighter than ever. But in the vast mixed areas, half or more of the lights went out in the six months leading up to the surge. They then stabilised in half-darkness. By the time the US troops arrived, there were no more mixed areas left. The easy pickings - the Shia who lived next door, or the Sunni who lived up the road - had all been attacked. Sunni and Shia weren't killing each other any more because they had retreated into vast enclaves, cleansed and armed, surrounded by barriers manned by militias. Four million people had been driven from their homes.
Professor Agnew explains: "Our findings suggest the surge has had no observable effect, except insofar as it has helped to provide a seal of approval for the process of ethno-sectarian neighbourhood homogenisation that is now largely achieved." The new US troops have simply built concrete walls between the newly-cleansed areas.
This study is a bleak vindication of my colleague Patrick Cockburn, who has been almost alone in telling the human story of the cleansing. Here's an example. In May 2006, four gunmen turned up at the house of Leila Mohammed, a pregnant mother of three children in north-east of Baghdad. "Be gone by evening prayers or we will kill you," they said. She was a Shia in a Sunni neighbourhood, so she had to run, or die. "Later I went back to try to get our furniture but there was too much shooting and I was trapped in our house," Leila said. "I came away with nothing." Now imagine millions of Leilas, and you have much of Iraq today.
Those who try to get past the checkpoints and walls to their old neighbourhoods find that the intercommunal hatred has not been soothed. Cockburn gives one typical example: "When one couple, both Shia, went last month to visit the house from which they had fled in the Sunni al-Makanik district of Dora in south Baghdad, they were immediately shot dead and their driver beheaded."
Yet Obama has failed to properly challenge this propaganda-surge about the surge. He echoes the McCain line that "the surge has succeeded beyond our wildest dreams", and shifts the conversation back to the decision to invade in the first place. He has evidently concluded that this case is too complex and too easily attacked with the ludicrous charge that he is "criticising the troops." So McCain is getting away with braying about the "great success" of wrapping one of the worst programmes of ethnic cleansing of our time in towering concrete walls of reinforcement.