Of course the preparations for war applied pressure on Saddam, and achieved results which wouldn't have been achieved otherwise. But the clear signs that war was intended regardless must surely have worked in the other direction - if you think it's pretty certain that you are going to be invaded anyway, that doesn't exactly encourage full hearted cooperation.

As for resistance to passing a resolution that would have given the USA what woudl have been claimed as legal sanction for going to war, regardless of anything that the inspectors might report - well,it would have been an enormous act of faith to vote for anything like that. And the sequel, which has had the USA and the UKL going to war unilaterally, regardless of the development of inspections and disarmament, and as soon as war preparations had been completed, demonstrates that any such act of faith would have been quite unjustified.

It all depends whether you believe the intention was in fact to achieve WMD disarmamment, or to invade Iraq in any case.