Personally, I doubt that President Reagan's public disapproval of Isreal's attack on the Iraqi breeder reactor was anything more than public posturing for the sake of our so-called "allies" in Saudi Arabia and the other so-called "moderate" Arab states. To the extent that I am incorrect on this, then the condemnation was wrong. Israel was absolutely correct to do what it did, and even I, a self-proclaimed liberal (at the time) had the sense to recognize it.
It is true, so far as I know, that Saddam has never threatened to use nukes against the U.S. But so what? Is he stupid enough to try to take on the U.S. directly? Probably not. Is he crazy enough to share WMD technology with those who will use them against the U.S.? Probably. Is he crazy enough to use them against the U.S.' only real ally in the region, i.e., Israel? Probably.
What will our excuse be? How about:
[1] The greater good of humanity clearly required it, so we did it.
or
[2] Sometimes good people must do bad things in order to prevent bad people from doing worse things.
As to reigning in China, I think you have it exactly 180 degrees wrong. The question to ask is, if the U.S. does NOT deal harshly with a petty tyrant like Saddam, how can it be counted on to protect Taiwan, when push comes to shove?
As to the Mad-Mullahs in Iran, they will do as they please, and, as your own statement demonstrates, they will make up the excuse as they go along. The only thing preventing Iran from attacking Israel is the IDF, the Mossad, and the implied threat of U.S. retaliation.
The burden of proof you propose is impossible to meet. Thus, what you are really advocating is doing nothing until such a time as lower Manhattan disappears under a mushroom cloud.
What if Neville Chamberlain had assassinated Adolf Hitler, rather than giving him the okay to take the Sudetenland, thus bringing the world, "peace in our day" as he so in-aptly termed it upon his return to Britain? History would now record him as a strange, perhaps tragic, murderer. And tens of millions of others would have lived on in happy ignorance, never knowing they owed him their lives.
As for better solutions, assassination is the only alternative I can think of which would achieve the desired result. Unfortunately, we don't have the capability to pull it off is such a tightly controlled society.
As for containment or buying influence, neither will work. How does one contain a promoter of terrorism who is himself a head of state, unless one is willing to attack that state? And how does one buy influence with such a thug? The only influence he cares about is within the Arab world, and the way to achieve influence in the Arab world is by killing Jews and/or killing Americans.
Finally, I am, frankly, quite surprised to see you parroting the James Carville-esque line that this all being about the elections. In a word, Bull! Shrub's intention to take out Saddam has been quite clear to anyone paying attention since September of last year.