I don't beat my wife, never have and never will
That was easy enough. I like John McCain's comments on this subject. He never did coke and has no problem stating that unequivocally.
Nice reasoning you had there but in actuality Bush never said anything like "I'm not dignifying that with an answer." What he said was more like "I'm not going to talk about my past. I've done things I'm not proud of and other people shouldn't do some of the things I've done etc etc etc..."
I think you should just face the facts. The man had his wild days, and cleaned up his act later and certainly made something of himself. I personally don't hold his drug and alcohol use against him. I only bring it up when confronted with right wing hypocrisy.
Hmmm I guess that means I talk about it all the time!