It is easy enough to make the analogy between the tragic folly in Vietnam and the chaotic disaster unfolding now in Iraq. Both were wars of choice, not of national necessity, and both were begun under a cloak of deception and misinformation. And in the future, both will serve as the dictionary definition of the word "quagmire."

The Vietnam analogy, however, only goes so far. By the time the war had escalated, the North Vietnamese had already established a working government in Hanoi, and their goal to consolidate the country enjoyed considerable support among the populace. When American forces were finally defeated, Vietnam experienced a mostly uneventful transition to peacetime and certainly didn't spiral into civil war.

By contrast, in Iraq right now, American troops are not fighting a single national organization or even organized rebel group, but dozens of factions. Nor in Iraq is there any group that commands enough widespread public legitimacy to be able to govern once American forces leave.

Historical analogies should never be drawn too tightly, but as Iraq descends further into fratricidal violence, it may be Cambodia, rather than Vietnam, that Iraq will come to resemble. And the Cambodian experience should make us feel even more grim about the mess we have made in Iraq.

Cambodia's fragile neutrality began to unravel in 1969 when President Nixon ordered secret — and almost surely illegal — bombing raids on Cambodia in his effort to chase North Vietnamese troops hiding across the border. For nearly three years, Cambodia became a theater in the Vietnam War. In 1973 alone, American bombers dropped more explosives on Cambodia than had been dropped on Japan in WWII, and after that stopped, Cambodia degenerated into a vicious civil war. In 1975, at virtually the same moment Americans left Vietnam, Khmer Rouge forces entered Phnom Penh triumphant.

The Khmer Rouge, under its leader Pol Pot, flew into a systematic, prolonged, genocidal rage, as it took its revenge against former opponents, imagined enemies and ordinary Cambodians for no reason at all. By the time the nightmare was over, perhaps as many as three million Cambodians were dead. Thirty years later, Iraq begins to look like Cambodia in several disturbing ways. Cambodia was, in the words of one journalist, a "sideshow" to the Vietnam conflict and to the struggle against Communism. Likewise, Iraq should never have been more than a sideshow in the so-called war on terror.

And both invasions have had the effect of strengthening the position of our purported enemies. By rescuing Cambodia from Pol Pot, Vietnam, the country we fought bitterly for more than decade, wound up exercising control over Cambodia for a generation. In the absence of a legitimate, widely supported government in Iraq, it doesn't take too much imagination to see Iran, the major menace in the Middle East, marching in overtly or covertly to provide the stability and order in Iraq that Americans clearly can't.

It is worth noting, too, that while Vietnam has made a remarkable economic comeback in the last decade, Cambodia still hasn't recovered from the events of the 1970s. Its economy is one of the poorest in the world, there has been little formal accounting of the genocide and dozens of Cambodians are still maimed each month by landmines. Cambodia is still a dangerous and demoralized place.

Perhaps things will turn out better in Iraq. There is oil, after all, and that may make the Iraqi future brighter. Still, even oil cannot undo the psychological effects of all the violence Iraqis have had to endure, nor can it protect Iraqis from the zealots with weapons now found there in such abundance. As in Cambodia, the Iraqi civil war may be brought to an end by some Muslim version of Pol Pot and supported by a population desperate for any promise of peace and security. As things move from bad to worse in Iraq, we may find ourselves wishing that Iraq was Arabic for Vietnam.