You said: if the motive behind the war in Iraq was empire, then even a decrease in terrorism and conflict wouldn't make it a "good war".

It is difficult to dismiss good consequences based on what you may perceive as questionable (actually misunderstood) motives. If we invaded Iraq with the idea of making it the 51st State both the motive and the consequences would be a disaster because we do not have the abilityor resources to do it. On the other hand, if we succeed in establishing a free, democratic, affluent and independent Iraq our questionable or misunderstood motives will become unimportant in light of the consequences. If we fail to accomplish our goals the motives will be just as unimportant in light of the consequences. Partial success may give us some redemption but it needs to go beyond just providing a measure of security to our country. There were other ways to do that.

For the best of all possible outcomes vs. motivation, consider the analogy of an alien race that drops by and tells us that they have been watching us for years and they don't like what they see. They announce that they are basically taking over. They cure all disease, end all hunger, educate all of humanity and resolve all religious conflicts. They advise us on the formation of a workable world government and eventually they leave after granting us membership in the Federation of Planets with full access to their technology and sovereignty over our solar system.

Did they impose their will on us? Did they acquire a new ally and trading partner? Were their motives selfish to impose change on us and pacify a dangerous species. The answer is yes to all and the results are a dream come true for humanity.

We are a far cry from the aliens in this fantasy and I can't fully guarantee all our motives or the outcome but I believe that our history suggests that we are striving for good consequences.

Modern nations should be shaping the world together but greed, jealousy and power lust infects us all. That does not mean that a nation or group of nations can't try to make things better if they have the ability to do so. We all have the same outcome in mind and that outcome does not include Islamic fundamentalism or anti-modernism.