The Clerics were not expected to hold the day, but rather be one party among many. Then, for whatever reason, a mustachioed Iraqi decided to lop off a peace of Iran by force; this instantly forced the Iranians to freeze the gradual sedimentation of their polity, and wage war. The clergy, being the best organized group in the country, ad the only political group that could mobilize people in every single hamlet of the country, was indispensable to this endeavor, and took full advantage of their irreplacability.
Saddam's behavior has never been completely explainable in rational terms, but, the Arab street, never bereft of conspiracy theories, does make much of the fact that Iraq was not punished for embarking on this war by the Western powers, but rather rewarded. Slapping an oil embargo on Iraq would have ended the war rather quickly, however, the prevailing mindset was best captured by Heinrich K.'s quip that "It was a pity that both sides couldn't lose."
My personal hunch is that the Arabs will in the end be the masters of their own fate, but that we, through hints and nudges can and could have helped them along. The imperative, however, has been to prevent nuclear war, the simplest and easiest way being to keep the countries mired in their own problems. In the end, the Arab world won't be able to modernize without some end to the conflict with Israel, and Israel will never see peace until the Arab world prospers. My money says that in the end, as in Germany, our soldiers will be needed on the ground to enforce peace.