Does the conflict in Iraq amount to a civil war? In many ways, the public debate over this question is largely political. Calling Iraq a "civil war" implies yet another failure for the Bush administration and adds force to the question of whether U.S. troops still have a constructive role to play.

Politics aside, however, the definition of civil war is not arbitrary. For some -- and perhaps especially Americans -- the term brings to mind all-out historical conflicts along the lines of the U.S. or Spanish civil wars. According to this notion, there will not be civil war in Iraq until we see mass mobilization of sectarian communities behind more or less conventional armies.

But a more standard definition is common today:

1) Civil war refers to a violent conflict between organized groups within a country that are fighting over control of the government, one side's separatist goals, or some divisive government policy.

By this measure, the war in Iraq has been a civil war not simply since the escalation of internecine killings following the bombing of a Shiite shrine in Samarra in February, but at least since the United States handed over formal control to an interim Iraqi government in June 2004.

Here's why: Although the insurgents target the U.S. military, they are also fighting the Shiite-dominated Iraqi government and killing large numbers of Iraqis. There is little reason to believe that if the United States were suddenly to withdraw its forces, they would not continue their battle to control or shape the government.

Political scientists who study civil war have proposed various refinements to this rough definition to deal with borderline cases. One issue concerns how much killing has to occur -- and at what rate.

2) For a conflict to qualify as a civil war, most academics use the threshold of 1,000 dead, which leads to the inclusion of a good number of low-intensity rural insurgencies.

Current estimates suggest that more than 25,000 Iraqis have been killed in fighting since the U.S.-led invasion in March 2003 -- a level and rate of killing that is comparable to numerous other conflicts that are commonly described as civil wars, such as those in Lebanon (1975-1990) and Sri Lanka (beginning in 1983).

The organization -- or rather, disorganization -- of the warring communities in Iraq means that a large-scale conventional conflict along the lines of the U.S. Civil War is unlikely to develop. More probable is a gradual escalation of the current "dirty war" between neighborhood militias that have loose ties to national political factions and are fighting almost as much within sectarian lines as across them.

This is roughly what happened in Lebanon and at a lower level in Turkish cities in the late 1970s. Ethnic cleansing will occur not as a systematic, centrally directed campaign (as in Bosnia), but as a result of people moving to escape danger.

And there's another twist to the terminology:

3) If the conflict in Iraq becomes purely a matter of violence between Sunni and Shiite communities driven by revenge and hatred rather than by political goals, many political scientists would say that it is something other than civil war.

Almost no one, for example, calls the Hindu-Muslim violence in India a civil war.

A civil war has to involve attempts to grab power at the center of government or in a given region, or to use violence to change some major government policy.

In Iraq's case, however, the vacuum of power at the center means that communal violence will inevitably be tied to struggles for political power and control.

A final complication concerns the nature of international involvement. Some argue, for example, that the war in Bosnia should be seen as an interstate war rather than a civil war, since the Bosnian Serb forces were armed and directed largely by Belgrade. Post-Mobutu violence in Congo is often termed a civil war, even though fighters have been closely tied to armies from neighboring states.

4) A conflict may be both a civil and an interstate war at the same time.

The Vietnam War, for instance, clearly comprised both a civil war in the South and an interstate war involving the North, the South and the United States.

Iraq may be moving in this direction. The United States and Britain are already openly involved, and such neighboring countries as Iran and Syria are more covertly involved. Not that it matters to the people dying there, but the next debate here may turn on whether what is already a civil war in Iraq should be viewed as an interstate war as well.

We hardly needed the 30th anniversary of the Vietnam War's end to remind us of that war. Iraq provides daily reminders, prompting frequent comparisons to Vietnam. While many of the analogies are misplaced, looking back at America's intervention in Vietnam can be valuable.

The major challenge now facing the United States in Iraq is to establish a stable and powerful indigenous military to provide a secure environment for nation-building.

The U.S. Army's initial unwillingness to integrate South Vietnamese soldiers into its military plans--and its later inability to motivate the indigenous troops to take over the fighting--tells us what to avoid in Iraq.

The old Iraqi army fell apart in April 2003 as American soldiers marched on Baghdad. As the insurgency grew and American casualties mounted, the coalition forces started putting Iraq's army together again. Many of the same soldiers came back to sign up--it was only at the higher levels that Baathist officers were purged. Both Iraq and the United States have an interest in strengthening a purely Iraqi force.

Still some lessons

President Bush calls the comparison of Iraq with Vietnam a "false analogy" and accuses those who use it of sending the wrong message to the enemy and to the troops. Likewise, Rep. Richard Baker, R-La., calls the analogy "wrong, disturbing and dangerous."

In fact, Vietnam does not make for a good comparison with Iraq--but the differences are informative. The most striking difference between the two situations is in the sequence of war and nation-building. In Vietnam, the United States attempted nation-building under South Vietnamese President Ngo Dinh Diem's administration for nearly a decade before intervening directly with ground troops; in Iraq, a short and overwhelming display of force preceded nation-building. Moreover, the Americans were facing a much stronger adversary--including an organized army--in Vietnam.

Beginning in 1969, the Nixon administration implemented its policy of "Vietnamization," withdrawing U.S. troops while simultaneously turning over to the Army of the Republic of Vietnam the fighting and the pacification efforts. By 1973, the South Vietnamese army was the strongest in Southeast Asia, boasting more than 1 million soldiers and toting the most advanced weaponry, thanks to U.S. Army programs such as Enhance and Enhance Plus. However, unimpressive performances during a joint incursion into Cambodia and the 1972 spring offensive testified otherwise. Finally, on April 30, 1975, Saigon fell to the communists. Where did Vietnamization go wrong?

From the entry of American ground forces in 1965, South Vietnamese forces were made to feel marginalized in defending South Vietnam. This was mainly due to the U.S. Army's belief in 1965-69 that the South Vietnamese troops were essentially irrelevant to victory or defeat. Not only were the soldiers equipped with inferior weapons, underpaid and given poor housing compared to their American counterparts, but they also were relegated to so-called pacification missions.

U.S. soldiers had more respect for their enemies from the North than for their allies in the South. Training and communication were beset with linguistic, social and cultural barriers. By the time South Vietnamese soldiers started replacing U.S. soldiers in 1969, it was too late to induce them to adopt what had come to be regarded as U.S. strategic goals, rather than South Vietnamese ones.

It's not too late

Now, in Iraq, a window of opportunity is still open for Americans. According to Anthony Cordesman of the Center for Strategic and International Studies, the United States wasted the whole first year after the invasion in halfhearted attempts to create effective Iraqi military and police forces. The bulk of the army is made up of soldiers who were fighting Americans a few months ago. Ethnic and religious divisions among the men, and their legacy of service under an autocrat, make it difficult for them to attain modern professional military standards. However, the Iraqi people are much less distrustful of the Iraqi army than they are of occupying U.S. forces.

The Multinational Security Transition Command, set up late last year, must focus on the Iraqi army's esprit de corps. It is not too late to incorporate and integrate Iraqi forces in strategic planning and operations so that they have a stake in securing a stable Iraq. Otherwise, the Iraqi army will soon be overwhelmed by the size and hostility of a growing insurgency.

The Vietnam analogy has too often been deployed in times of political conflict in the United States. But the comparison can be useful. If we learn the right lessons from the mistakes in Vietnam, we need not be condemned to repeat them in Iraq.