It's fundamentally different.
It may very well happen that Iraq becomes a shining example of Arab "liberalism" in the real Jeffersonian sense. We then have a buddy in the region to replace Saudi Arabia. We are happy. They are happy. Israel is told to shut up and behave itself. This is not Lebensraum or Rassenvernichtung. It's "revolutionary politics" as described by T.L. Friedmann of the Times, who, as was pointed out by Alex, knows the people and the region. I might point out that the Republicans were born as a party with just such a revolutionary mandate against the South. They invaded and imposed their will on a sovereign nation. Even before that, a similar invasion of Mexico was undertaken, that is eerily like the current war in context.
Does that make the war correct? NO. The end does not justify the means. Once you start living that way, there is no bottom to your responsibilities to make God-like decisions. It is better to order one's own house first, to set an example to be followed by people of their own free will.
It is strange - the Christians have the opportunity to show all the Semitic people how to live according to sane principles of compassion, but instead resort to the authoritarian principles that organize the competing faiths.