I was given to understand the "could restore us to sanity" part was solely in reference to the strange mental twist I had regarding another drink being a good idea at times. Obviously I didn't have or was likely to magically develop that ability to any really useful degree.
The convincer for me was the number of alcoholics I saw who believed they had that who drank again. There is never a shortage of quality visual aids in our crowd, so paying attention to results pays off often.
The personal conception I developed during the course of step 2 had that amount of power, to get between me and my next drink. "could" was answered for me. "would" demanded trust and decision, which is partly what step 3 resolved.