One of the interesting effects of the Iraq war debate has been to give war opponents -- most of them pacifists, leftists or internationalists -- more of an understanding for traditional realist views of foreign policy.
Most conflict, most of the time, is not about ideology, but about ethnic identity and resources, especially land (blood and soil).
The first genuinely ideological wars started with the expansion of Islam. Christianity and Islam are both very clear about the insignificance of tribe in comparison to belief. Same with Protestantism and Catholicism. Then we get the liberal wars and revolutions of the nineteenth century and the Cold War. But even, in these conflicts, the Crusaders sack Constantinople, Protestant English and Dutch fight about the wool trade and Nixon goes to China. In other words, even when there is a clear ideological division -- which everyone involved theoretically considers more important than tribe -- tribe often wins out.
Most people are comfortable with this. But there are always a few ideologues who thrill to fighting for an idea, but do not like fighting for revenge or conquest. But after the Cold War, it was hard to justify conflicts in terms of ideology, although some saw a universal regime of human rights as a basis for intervention. Others, on the right, were nostalgic for the old Cold War and looked around the world for plausible candidates for a new one.
Then came September 11.
I suspect most Americans viewed the Iraq war as payback against Arabs for an Arab attack on them. The logic is genocidal, but it is also perfectly human. But you can't quite come out and say things that crudely. So we had to have a justification that foreign policy elites would find acceptable, and hit on nonproliferation.
The lack of WMDs then drove war proponents to a Trotskyist explanation of their support for the war: it became the duty of the United States, as a proposition nation, to extend the democratic revolution to the ends of the earth. Ethnic conflicts (like those between Israelis and Palestinians) are shoehorned into an ideological framework.
The difficulty is that a democratic revolution in the Arab world will mostly benefit anti-Israeli Islamists. The Arab world is not Eastern Europe in the seventies, with an opposition centered around novel-writing bohemian liberals. Such people exist in the Arab world, but they have no popular base at all, and are more likely to survive with traditional dictators than with a genuinely popular regime. With the election of Hamas, it became impossible to ignore this reality.
It is still possible to believe that Islamism will only be a stage in the democratic development of the Arab world. Islamists in power will lose their appeal Maybe we are seeing that right now in Palestine (although the latest Israeli invasion is bound to polarize things again).
But if we accept this, then we are imagining a war -- in retaliation for Islamist attacks -- designed to put Islamists in power to further the development of history. Dialectical thinking becomes madness.
The realists and isolationists at least have this going for them -- if the West can't know what to do, then surely it is better to do nothing. The Arab world is bound to go through turmoil -- so we are better off not to have a direct hand in it. If the cunning of reason works out in the end -- if it is really everyone's destiny to become a contented bourgeois liberal democrat -- then it can do its work alone. If not, well then we are better off without that particular illusion.