I have finally finished Bernard Lewis!
He explains clearly here, why the two main reasons commonly given for not waging war against Saddam Hussein are mistaken.

"The conflict with Israel certainly receives overwhelmingly major attention in the Arabic media, but since this is the only specific grievance that may be publicly expressed in a region of numerous and painful problems, that is hardly surprising. One may therefore wonder whether Middle Eastern governments would indeed wish for a peace settlement, which would deprive them of this valuable safety valve, leaving them to face the undeflected anger of their subjects, including those who live under the rule of the Palestinian Authority. From the almost monotonous regularity with which a series of promising peace processes have failed at the moment when they seemed most likely to succeed, one may be driven to the conclusion that they prefer to keep the conflict unresolved, but at a low level--simmering not boiling, and usefully controllable".