Neocons aren't really conservatives. They are people who have recently abandoned liberalism but aren't, by definition conservatives. Neocon is a word coined by the left to identify the "traitors".
The treaty was not to end the war. The treaty was to maintain a cease fire.
When our allies are attacked, we are attacked. We had a treaty with Kuwait and were required by law to come to their aid.
The founders of this nation accepted help from several nations, france being the principal to support their efforts to become free from the king. When we sign treatys, we become entangled in foriegn affairs, and the founders certainly signed treaties with foriegn powers. I am a conservative's conservative and I find nothing within the philosophy that would prohibit me from supporting a war against a hostile government.
The plan is to introduce them to freedom. Free people generally don't threaten their neighbors and free people generally don't tolerate violent factions operating within their sphere of influence. A free iraq will no more tolerate radical islamists operating openly than we would. And there is every reson to expect a domino effect through the reigon if iraq becomes a free nation. The populations of islamic countries are ripe to get out from under the repressive thumbs of their keepers and it is to our advantage to help them whenever possible.
We are dealing with a group of people who have a 15th century mindset and unless we bring them (kicking and screaming if necessary) into the 20th century, they will continue to be agressors in exactly the same manner they were when they started the war that became the crusades.