Why did we got to war?

I thought it was because Saddam had (we thought) WMDs. But others have said that that's only one reason, and even a minor one. For instance, Jonah Goldberg wrote the following today:

Anyway, my point is this: to the extent the post-Iraq failure to find WMDs is a disaster for the United States in terms of its credibility, its relationships with allies etc. one could argue that the fault lies in the fact that George W. Bush listened too much to Colin Powell and the State Department instead of the hawks, since it was the Wolfowitz crowd which wanted to emphasize freedom, democracy, stability and the war on terror. Now that no WMDs have been found that rhetoric seems self-serving when in fact those were co-equal priorities all along. If George Bush had talked before the war about bringing freedom and democracy to Iraq as eloquently as he did afterwards, he would be in a lot better shape politically and in the history books. Moreover, I bet he would have been a lot more honest. Bush is a moralist and I'm certain he had the liberation of Iraq and the war on terrorism in his mind as much as anything else.

Now, I like Jonah; he's a great writer, whose material I really enjoy reading.

But I think he's all wet on this one. Simply put, I don't think the very noble goal of bringing democracy and stability to Iraq and thus (hopefully) to the region is sufficient grounds to launch a war, and I've never seen someone who argued for the war on the basis of just war doctrine attempt to do so.