Bush Sr. stopped the 1991 War for a few reasons. First, he had no UN mandate to go all the way to Baghdad. Second, he was convinced by other Arab states, (and probably France and Russia) that Saddam provided stability. The Saudis were scared to death of radical Islam coming from Iran, and they thought that Iraq was a buffer. In the end of course they got it anyway. Third, the visual images of the US rolling over Saddams army were disturbing, and the US was worried about appearing the bully. And lastly, sanctions, were percieved at the time to be a more "humane" approach than war, infact sanctions were all the buzz of the anti-war crowd including Chomsky. Everyone thought that Saddam would be overthrown, or would become the next Qaddafi, not very palatable, but acceptable.
The ultimate irony is that Saddam ended up being far more brutal in supressing his opposition that anyone expected, he resisted inspections for years, he survived coups, and he flourished by finding routes of smuggling and kickbacks. Not only that, his propaganda machine was very effecive at deflecting the balme from him to the US.
In light of this, he has written the handbook on "how to survive sanctions". Because he has shown others the way to outlast the community will, I would endeavor to say that sanctions are dead as a doornail. Undoubtedly some other bad actor will come upon the world stage, and sanctions will be proposed again, and we will be told why, "this time it is different". I can't imagine that debate going too far.
The US has carried away the lesson that you should only fight once. Prior to this century going into battle and NOT fully defeating your foe would be laughable. I think that the US will never again accept a mandate for anything less than full victory. Given the fact that most western countries have military spending that is an all time low in comparison to their GDP, the US military will bear the brunt of any "world effort".
In the end Rhia, you are absolutely correct, diplomacy and war are the only proven methods of international change. Since only the US has the war machine that is proven, that means that big dollar bribery is going to be the method of choice short of war.