Let's with the more familiar notion: Symmetric warfare is when both sides have more or less the same weapons and tactics. In World War II, for example, the German tanks, planes, and machine guns battled the Allied tanks, planes, and machine guns. In the American Civil War, blue and grey alike had cannons and rifles and cavalry. In a conventional symmetric war, armies take and hold territory, there's a front line, and it's not too hard to tell the difference between soldiers and civilians.

Brutal and destructive as it can be, symmetric warfare has become (to a certain extent) civilized. There are rules. Soldiers wear uniforms so that you can tell who they are rather than shooting everything that moves. When soldiers surrender, a whole set of gentlemen's agreements come into play. Soldiers are like chess pieces; once captured they are removed from the board and kept safe until the end of the game. International agreements also proscribe the use of indiscriminate weapons like poison gas or disease.

These rules developed over centuries when warfare in Europe really was a kind of game. Wars centered on issues of little consequence to the average person: which brother would be king, whether your town sent tribute payments to Paris or to Vienna, and so on. If you were a civilian, you kept your head down, waited for the dust to settle, and then paid your taxes to the winner. Even soldiers were playing a kind of game. Some were mercenaries who fought under many different flags in the course of a career. Others (like my Alsatian ancestors) came from border provinces, and so owed their allegiance to whichever king had won the previous war. You did your job, but after the outcome was clear there was no sense getting yourself killed.

When wars were fought over something that struck deeper - like the Crusades or the Catholic/Protestant wars of the 1600's - rules went out the window. The Thirty Years War, for example, depopulated entire regions of central Europe.

When Losers Don't Quit

Asymmetric warfare happens when it's obvious who the winner of a symmetric war would be - maybe a symmetric war has already been fought and decisively won - but some core group on the losing side is not willing to give up and get on with life. Replaying the game of civilized symmetric warfare would just get them slaughtered to no purpose, but the issues of the war are so important that they cannot simply accept defeat. And so they fight on - outside the game, outside the rules.

Asymmetric warriors don't wear uniforms and fight pitched battles. Rather than defending territory, they accept that the opposing force can go where it wants, killing and destroying at will. They hide among civilians, they hit and run, and they attack whatever targets their enemy values but has left undefended. Often those targets are non-combatants.

To the winners of the symmetric war (and all others who remain locked into the game mentality of symmetric warfare) the asymmetric warriors just look like sore losers. If the asymmetric warriors were civilized and honorable, they would wear uniforms and face their opponents' soldiers on a battlefield - and get slaughtered like vermin. The asymmetric tactics - attacking civilians and running away from soldiers - look cowardly, even when they lead to certain death. And because the decisive war is already supposed to be over, an asymmetric attack looks like pointless destruction, killing for the sake of killing.

And it would be, if not for one fact: Sometimes the asymmetric warriors win. How on Earth does that happen?

How Insurgents Win

Asymmetric warfare works in a very specific situation: The winner of the symmetric war wants to govern the region (or hand it off to a local client government) at a finite cost. If the asymmetric warriors - in this setting let's call them insurgents and their opponents occupiers - can make the territory ungovernable and establish themselves in such a way that they cannot be crushed within the cost parameters of the occupiers, then eventually the occupiers will have to give them at least part of what they want.

In other words, insurgents win by not losing. If the occupiers find the status quo unacceptable, but have no acceptable way to bring the insurgency to an end, then it is only a matter of time before they realize their goals cannot be achieved. It's up to the occupiers to decide when to stop the bleeding and admit defeat, but they have lost. This is the story of the Americans in Vietnam, the Soviets in Afghanistan, and white settler governments in various parts of Africa. It is arguably the story of the Americans in Iraq as well.

(It is worth noting why this is not - at least not yet - the story of Israel in the West Bank and Gaza. The difference is that the Israeli level of commitment very nearly matches that of its opponents. Israel is unable to crush the Palestinian insurgency, but seems ready to bleed at this level into the indefinite future.)

Americans have a hard time grasping this basic fact: Right up to the day the occupying power admits defeat and pulls out, it continues to wield overwhelming force. It may never lose a pitched battle. It may - right up to the end - be able to go where it wants, killing and destroying at will.

That doesn't mean it's not losing.

The Recruitment Pipeline

If insurgents win by not losing, then the question shifts: How do they lose?

They lose by wasting away. Their numbers diminish by death, captivity, or discouragement and they are unable to replenish themselves with new recruits. Recruiting is an essential part of any insurgency, because the occupiers will always appear to be winning the battle of attrition. Occupying soldiers are trying to kill insurgents while insurgents are trying to avoid occupiers, so any body count will favor the occupiers - right up to the day they admit defeat and pull out.

In a successful insurgency, warriors are only the tip of a large iceberg. Even though the number of active warriors may be small, a much larger segment of the population is at some earlier stage of recruitment. Some sympathize with the insurgents silently; they know who the warriors are, but chose not to tell the occupiers. Some help in small ways, by delivering messages, holding money, or even hiding weapons. Some harbor warriors and help them hide from the occupiers. Some will not fight, but will act as look-outs and report the movements of occupying troops. A successful insurgency is always losing warriors (sometimes by intentional suicide attacks), but the pipeline of recruitment is full of people moving to ever greater levels of commitment.

Occupiers who continue to think in a symmetric, conventional-war mindset (with its sharp distinctions between soldiers and civilians) do not see these flows of sympathy and commitment. If the insurgency has, say, ten thousand warriors, then these occupiers believe they win by removing ten thousand insurgent pieces from the board.

But they don't win, because in the course of removing those ten thousand pieces the occupiers push some number of sympathizers further down the path of commitment to the insurgency. Ten, twenty, thirty thousand insurgents may die or be captured, and still the war goes on. A man who stays out of the war for fear of losing his house will join it when his house becomes "collateral damage." Each family that loses a member in an occupier attack - especially an innocent member like a child - will move further down the path of recruitment.

In the beginning, an insurgency is a small group of warriors moving in a large sea of people who are waiting to see what happens next. Maybe the occupier will be gentle. Maybe life will go on in some acceptable way. The insurgents' first goal is to goad the occupier into using its overwhelming force so that life cannot go on in an acceptable way. A foolish occupier swats flies with hammers, creating disproportionate damage and forcing the previously ambivalent population to choose sides.

Once the insurgency's pipeline of recruitment is well established, the only exclusively military solution available to the occupier is genocide, or some form of ethnic cleansing that will move the insurgent-sympathizing population somewhere else. An occupier who is unwilling to go that far must accept the fact that overwhelming force alone is not enough. Military force must continue to play a role, but only in support of a political solution that gives the asymmetric warriors a reason to lay down their arms.

Occupier Strategy

If a direct kill-the-insurgents strategy is doomed to failure, what can the occupier do?

The Vietnam-era notion of "winning hearts and minds" is not just a way for guilt-ridden liberals to feel better about themselves. It deals with the real problem: the whole pipeline of sympathy and recruitment, not just the comparatively small number of active insurgent warriors. Every policy of the occupier - and especially any use of force - must be examined in light of its effect on insurgent recruitment. A search-and-destroy operation may kill dozens of insurgents with only minor occupier casualties, and still be a net loss if it pushes the general population further down the recruitment pipeline. A lawnmower may cut down dozens of dandelions, but if it scatters their seeds hundreds more will pop up.

All effective anti-insurgent strategies involve drying up the supply of recruits by isolating the insurgents from the larger population. In the so-called "ink spot" strategies the isolation is geographic: a small area is pacified and reconstructed to the point that it becomes governable. The population, seeing the benefits of peaceful governance, resists insurgent efforts to infiltrate. The surrounding areas come to envy the pacified area, and the governable "ink spot" spreads. Other kinds of isolation can also work, as long as the population comes to see a clear separation between itself and the insurgents rather than a slippery slope.

Insurgency by its nature is a low-lifespan occupation. Lenin's line about revolutionaries - that they are dead men on furlough - applies even moreso to insurgents. They must take action to stay relevant, and any action they take carries great risk. Without a constant resupply of recruits ready to die, an insurgency withers.

In order to disrupt that supply, the occupier need not be loved. It need only convince the population that ending the occupation is not worth dying for.

The Anti-Timetable Fallacy

Much current rhetoric falls apart once these basic principles are understood. For example, consider the Bush administration's main argument against setting a timetable for withdrawing American troops from Iraq: that the insurgents would bide their time until we had left, and then rise up again.

If only they would.

Think about it: Suppose the insurgents sat on their hands for a year while they waited for us to withdraw. Iraq, in other words, gets a year of peaceful governance and reconstruction. Roads and power plants are built. Businesses are started. Pipelines transport oil without interruption while tens of billions of petrodollars flow into the country. People rebuild their homes, get jobs, enroll their children in school. And most of all, old wounds recede ever farther into the past.

What happens to the insurgent recruitment pipeline during that year? It collapses. In the course of that year, many people who thought they were willing to die would realize they had something to live for. No insurgent leader could allow it.

I don't know what actually would happen if the U.S. announced a timetable for withdrawal, and maybe there are legitimate reasons to be against such a move. But I guarantee that the insurgents would not sit back and wait for us to leave.

Hezbollah

Finally, we come to the issue of the day: Israel and Hezbollah.

"Israel has a right to defend herself," President Bush said at a recent news conference. I have no argument with that statement, I just think it is completely irrelevant. Nations and individuals have a right to do all kinds of misguided things. And that's what I think Israel has done.

I understand the provocation. Israel/Lebanon/Hezbollah has some parallels with America/Afghanistan/Al Qaeda after 9-11. Israel has been attacked by Hezbollah forces in Lebanon, and the Lebanese government is either unable or unwilling to do anything to prevent future attacks. Any responsible Israeli leader would be trying to figure out how to defend its people and territory.

But that doesn't mean going in with the hammers and lawnmowers. Israeli rhetoric about destroying Hezbollah as a fighting force is detached from reality. At most, the Israelis can hope to kill some large number of Hezbollah fighters and capture or destroy the current supply of rockets. But all of that is easily replaced: Iran can send more rockets, and the number of people willing to die in order to kill Israelis has surely gone up in the past few weeks. Killing your enemies, if it's done badly, increases their number.

War: What's It Good For?

Like most liberals, I am not a pacifist. I believe military power has its uses, and it does some things very well. If, for example, our goal in Iraq had just been to capture Saddam - well, we did that, didn't we? A similar operation might have captured Bin Laden. Bosnia is far from paradise these days, but at least people aren't dying by the tens of thousands. With similar care the genocide in Rwanda might have been stopped, and the one in Darfur still could be. And if anyone knew a way to go into North Korea and come out a few days later with Kim Jong-il and all the North Korean nuclear weapons, I'd be for it.

But military force is a blunt instrument, and used badly it creates more enemies than it kills. If you're not prepared to kill millions of people - and I'm not - then you have to find a way to circumscribe your enemies, so their numbers aren't instantly replenished, with interest, as soon as you kill them. In the long run, if you aren't willing to commit genocide against your enemy's recruitment pool, then every use of force has to be carefully calibrated.

Because it might not be a pool, it might be an aquifer.