CIVIL WAR occurs when the last vestige of civility collapses. It is the merciless, intimate, internecine “war of every man against every man” imagined by Thomas Hobbes: “No arts, no letters, no society, and which is worst of all, continual fear of danger and violent death.” Civil war is the war of brother against brother, neighbour against neighbour, tribe against tribe. It often begins in ideology or ethnicity, but it is sustained by vengeance, feud building on feud, in a cycle of murder that can last for generations.

We think of civil war as the ultimate barbarity, yet it is the rule more than the exception in recent history. Over the past half century, about 3.3 million people have died in battle as a result of wars between countries, each lasting on average for three months; during the same period, about 16 million people perished in 127 civil wars, with an average duration of six years. Civil war is far more widespread, bloody and sustained than war itself.

In Britain and America, civil war comes freighted with historical resonance, the very antithesis of a society that is stable and free. Britain’s parliamentary democracy was profoundly shaped by a gruesome civil war; America’s ideal of nationhood was founded on the resolution of a civil war that nearly shattered the country.

For months, we have heard that Iraq is on the brink, the cusp, the verge of civil war. But the ugly truth is that by every practical definition — historical, numerical and political — Iraq is already in the grip of a civil war.

The White House and Downing Street studiously avoid this loaded term. Indeed, there is a Pentagon official whose task it is to take issue with academics who argue that civil war has begun. Instead, the conflict is described in the traditional language of conventional war and its aftermath: “insurgency” and “counter-insurgency”, “rejectionists” and “loyalists”.

True, we have not yet seen the nationwide conflagration of inter-communal killing and ethnic cleansing predicted by many after the bombing of the Shia shrine in Samarra on February 22. The civil war is not yet total, but it is active and expanding, gradually engulfing the rival Sunni and Shia communities that make up three-quarters of the Iraqi population.

This is not a just a matter of semantics. A civil war is qualitatively different from any other sort of conflict, a violent struggle between organised groups for control of the centre, characterised by conflict between rival militias, lethal inter-communal reprisals and the steady erosion of central control as the political fissures spread outwards. The US-led coalition continues to portray the violence as the work of a group of rebels seeking to oust a government, democratically elected by the Iraqi people and defended by US and British armed forces. The evidence, however, suggests that the war has moved into a new phase, with Shia battling Sunni regardless of the Iraqi government or the external military power, with each side operating its own death squads. Sunni and Shia, inheritors of an ancient sectarian conflict dating back 14 centuries, are now competing violently, not just for political power, but for Iraq’s oil riches.

According to a New York Times survey, towns around Baghdad that were once home to a mixed population of Sunnis and Shia, are splitting along sectarian lines. There is strong evidence that if US troops pulled out, full-blown carnage would ensue; but it is now doubtful that third-party force alone can now stop it. The internal conflict has already developed the self-propelling momentum of a classic civil war, but the occupying forces have yet to acknowledge it.

Asked recently about the mounting violence, George Bush stolidly insisted: “The troops are chasing down the terrorists.” But in a civil war identifying the terrorists becomes much harder, while the troops risk being seen as pro-Shia partisans in the spiralling conflict. The Bush-Blair collation has put its faith in strengthening the Iraqi security forces, but those forces are themselves dominated by Shia, and thus regarded as a tool of oppression by many Sunnis.

As Paul Starobin points out in a bleak but brilliant assessment in The National Journal, civil wars tend to end only when one side crushes the other. If it came to an all-out communal war, the majority Shia would probably win, but at a cost of inflaming the entire region, for the implications of Iraq’s civil war extend far beyond her borders. Like the Spanish Civil War, the conflict would surely draw in neighbours: Sunnis from Saudi Arabia and Jordan in support of Iraqi Sunnis, Iranian Shia backing their co-religionists.

The civil war in Bosnia was ended by outside intervention, but in Iraq it was military action by outsiders that created the power vacuum into which civil war erupted. Civil wars may peter out through sheer psychological exhaustion, when the cycle of reprisal and revenge finally runs its course, as happened in Algeria; boredom played an important part in subduing the conflict in Northern Ireland. In Iraq, that point seems bloodily distant.

Up to 20,000 Iraqis have been killed since the end of combat operations in April 2003, yet the US and Britain remain locked in the belief that this is still a situation analogous to Vietnam, with brutal terrorist insurgents dedicated to overthrowing the government.

Abraham Lincoln observed of the American Civil War: “All dreaded it. All sought to avert it. And the war came.” The same elements of wishful thinking are evident today in Iraq. We dread civil war, and rightly, but no amount of dread has been able to avert it.

There may still be time to prevent the civil war in Iraq from spreading into anarchy, and on to a regional scale. Iraq has a long history of communal peace between Sunnis and Shia. But resurrecting that peace requires a supreme effort by Iraq’s sectarian leaders to pull back from the point of no return, and a clear-eyed realisation in the US and Britain that civil war in Iraq is no longer just a grim prospect, but a reality.

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