How about this?
"Had I known at the time that, as you [Bush] now assert, war was a foregone consequence of my vote, that the inspections process was something that, from the beginning, you had no intention of honoring, I most certainly would not have voted for it. But that wasn't what you promised, and that wasn't the proposition that was before the Senate."
That's good. I suppose it's the old "I was duped" argument, but well put.
well, it's only "i was duped" if Bush sticks to the position that the Senate resolution was a vote for war. If Bush stays with that, then he admits that the whole prelude to the war was a transparently empty charade. And though most supporters of the war freely admit exactly that, for the leader of the free world to own such a thing would be catastrophic, I think. More catastrophic than Kerry's implicit admission that he had been played.
So I think Bush will retreat from that talking point, at least if he is confronted with its implications in a sufficiently dramatic way. Then we would be back to "what was the rush? why not let the inspections continue?", questions Bush has no good answer for (since he will have just taken "it was time for Saddam to go" off the table).