For some time it has seemed to me that the most important distinction determining how people view the conflict in Iraq is based upon different conceptions of what exactly the war is about.

One group looks at the war as being primarily about who rules Iraq. We went to war to evict Saddam Hussein, we stayed in Iraq primarily to replace Hussein with a friendly Democratic regime, and should stay or go largely based upon the probability of success and a judgment about how much we are or should be willing to pay in lives and treasure for that outcome.

The other group looks at the war in Iraq as not being primarily about who rules Iraq, but instead as the primary battlefront in the so-called “war on terror,” or as I would prefer to call it the war on Islamic fascism. In this view, successfully replacing Saddam Hussein’s tyrannical regime with a Western-leaning Democracy would be a huge blow to Islamic fascist movement, but ultimately winning the “war” in Iraq should rightly be seen as an important step in winning the larger conflict, not as an end in itself.

Obviously if the first view is correct and the current fighting and dying in Iraq is simply about installing the kind of regime we want to see in Iraq, Americans are right to be asking the Bush Administration about just how costly achieving this goal will be, and just how likely are we to achieve it. After all, the American government exists primarily to defend Americans and their interests, and it is not unreasonable for most citizens to have a limit to their tolerance of our leaders pursuing costly altruistic goals with limited chances of success.

Obviously, most of the calls for withdrawal from Iraq come from people in this camp, who argue that the goal Bush has set is difficult or impossible to achieve, the costs are too high, and the consequences of failure are limited. So what if Iraq is ruled by a tyrant? As long as we can contain him, what business is it of ours? It is reasoning such as this that led to our withdrawal from Vietnam, and whatever you think of the results, it is clear that Vietnam never presented an existential threat to the United States.

However, if you begin with the premise that Iraq is simply the most important front in a global war between fundamentally incompatible worlds, the world governed as liberal democracies and the expansionist world governed by Islamic fascists, the equation changes quite a bit.

If Iraq is simply the current battleground between two types of societies that cannot but clash, then the issue isn’t whether we will be at war or not, but where the fighting will take place. In other words, Americans do not really have the power to choose war or peace with Islamic fascism; the war has been declared and is going on as we speak. Choosing to leave Iraq will only change where the war is fought, not whether there will be fighting.

There is ample evidence that this view is much closer to reality than the first. Whatever motivates the individual militias we are fighting in Iraq, it is clear that the fighting persists at this level because Iran and Syria see the war in Iraq as an opportunity to strike a blow to the Great Satan. In fact, Iran’s support for militias—on both sides of the fighting in Iraq—is part of a larger strategy to undermine Western Societies and Western power that includes the pursuit of nuclear weapons, the training and export of terrorists, and the fomenting of religious violence all around the world.

Iranian President Mahmoud Ahmadinejad has been very clear about his desires and intentions regarding this larger world conflict. There is, in fact, no ambiguity at all about his desire to wipe Israel off the map of the Middle East, and few serious people would doubt his willingness to use nuclear weapons to do so when the opportunity arises. Iran’s pursuit of advanced missile technology adds a new dimension to the threat—both Europe and eventually the United States will have to deal with a genuine nuclear threat from Iran, either using these weapons as bombs or as EMP devices.

And Ahmadinejad’s antipathy to the West is not, on its own terms, irrational. The Islamic fascist view of the ideal society is in fact incompatible with the existence of Western Liberal democracies. As long as the BBC, Sky TV, and Hollywood keep pumping out news and entertainment that tempts young and impressionable Muslims down the path to hell, Iran’s leaders (and all those dedicated to a robust religiously ruled Islamic State, including Al Qaeda) will dedicate themselves to destroying liberal societies.

If the war in Iraq is primarily the current battlefront in a larger war, the costs of leaving the battlefield are potentially huge. As seemingly costly as this war has been, by any historical standard the costs have been quite modest. Further, by fighting the war in Iraq, the United States has taken to war to a battlefield upon which our enemies cannot afford to lose. Iran, Syria, and in fact all the most radical elements throughout the Middle East could not easily tolerate or even survive the existence of a free, prosperous, and Democratic Iraq in their midst. As long as we are concentrating our forces in Iraq and seem likely to continue the fight, our enemies will throw everything they have at us there—lowering the chances of successful strikes against our vital interests and territory elsewhere.

If the West chooses to abandon the fight in Iraq, not only will that country fall to our Islamic Fascist enemies, but we will be freeing up the enormous resources they are expending to defeat us there. Resources that can be turned against us here at home or in Europe. And instead of having US forces stationed on the border of Iran and Syria, ready to menace them if necessary, we will have reduced our military threat to them without reducing the cultural threat they need to eliminate. It would be a huge victory for them in their war against us.

Given all this—if you accept the assumption that the war between the West and Islamic fascism is inescapable—leaving Iraq would be irrational. Our total casualties in 3 years of war there are substantially less than we suffered in the battle of Okinawa (12,000 dead in less than 3 months).

The Iraq war, when viewed discretely, may appear to have the United States as paying a very high price for a goal that frankly is nice—democracy in Iraq—but not vital to our interests. But if you view the war as part of a larger conflict, then the costs are put into a very different perspective. Indeed, if you believe that Islamic fascism is an existential threat to liberal democracy, and vice versa, tying up the enemies’ forces in Iraq for years looks like a pretty good bargain.

So which view is right? We may never know if Bush succeeds in continuing the battle in Iraq, either succeeding in establishing a democracy or at least tying up the enemies’ forces for years. Alternatively, we may find out if those who want to pull out get their wish: if the conflict in Iraq is simply about who rules that country, then our retreat will hurt our prestige but not endanger the country; if Iraq is simply one front in a greater war, we may soon be wishing that we had “surged” those troops years before, instead of pulling them out.

The new front in the war, then, would be here.