Iraq is back in the headlines in the US. On the campaign trail John McCain has repeatedly attacked Barack Obama for his failure last year to support the Bush Administration's surge of an extra 30,000 troops to Iraq.
McCain continues to argue that it is the surge that has driven the steep decline in political violence over the past 12 months. But he is wrong.
The three developments that were most effective in driving down the fatality rate in Iraq had little to do with the deployment of thousands of extra US troops.
First was the security impact of forced population movements. The good news about declining civilian deaths, particularly in Baghdad, was due in part to the bad news about ''ethnic cleansing''. Sectarian violence continued to drive people from their homes in the Iraqi capital throughout the surge build-up in the first half of 2007. Areas controlled by the Shi'ites expanded in the north of the city, while the Sunnis, who were mostly on the losing side, consolidated in the south.
The sharply redrawn sectarian boundaries that were the result of ethnic cleansing created more defensible space for both communities, while far fewer vulnerable, mixed neighbourhoods meant that there was less territory to fight about.
The second factor was the unilateral ceasefire put into effect in August 2007 by the leader of the powerful, but deeply factionalised Mahdi Army, Moqtada al-Sadr. In mid-November last year the US military reported that the ceasefire had been a significant factor behind the drop in attacks in Baghdad. The ceasefire had nothing to do with the surge.
Finally, there was the surprising alliance formed between the US military and its former Sunni insurgent enemies against the terrorist group al-Qaeda In Iraq. This too had little to do with the surge.
From 2005 into 2006, the Sunni militants of al-Qaeda in Iraq had been pursuing a nationwide terror campaign against Iraq's Shi'ite community.
The suicide bombings of Shi'ite mosques and other civilian targets were intended to provoke revenge attacks against Sunni communities that would precipitate a Sunni-Shi'ite civil war.
The resulting violent anarchy would, the Iraqi al-Qaeda leaders believed, lead to the withdrawal of the US and its allies.
The strategy backfired. The indiscriminate anti-Shi'ite violence from al-Qaeda in Iraq, plus the militants' efforts to impose their extremist ideology on the local Sunni populace in al-Anbar province and elsewhere, had generated growing Sunni anger throughout Iraq.
This intense and growing popular revulsion became a major strategic liability for the militants, not least because it paved the way for the unprecedented US-Sunni security collaboration that had gathered pace in the last half of 2006, long before the surge, and accelerated throughout 2007.
Sunni insurgents, who had previously been killing Americans, were now working alongside them in a campaign to hunt down and kill their former al-Qaeda-in-Iraq allies.
Throughout 2007, as part of the extraordinary process that had become known as the Sunni awakening, tens of thousands of mostly young Sunni men, many of them former insurgents, flocked to join the new anti-al-Qaeda concerned local citizens' militias, large numbers of which were armed and funded by the United States.
The US military's new Sunni allies provided priceless intelligence on the identity and location of al-Qaeda-in-Iraq fighters with some of the most valuable information coming from their defectors who had joined the new militias.
By the late northern summer of 2007, the combined efforts of US forces and the Sunni concerned local citizens' groups had dealt a series of crushing blows to al-Qaeda in Iraq in most of its urban strongholds in the country, which was a dramatic reversal of the terror group's fortunes in a relatively short period oftime.
While Iraq's future security remains uncertain in many respects, one thing is very clear: al-Qaeda in Iraq, while far from being completely crushed, has suffered a stunning defeat, politically as well as militarily.
Hated by both the Shi'ite and Kurdish communities and having deeply alienated its former Sunni allies, there is little prospect that it will ever make a comeback.
The surge has undoubtedly played a modestly positive security role in Iraq but, contrary to Senator McCain's assertion, it has not been the major factor driving that country's welcome decline in violence.
Andrew Mack is director of the Human Security Research Project at Simon Fraser University in Vancouver.
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