The wind blown hair, verbal stumbling and repeated requests for what the empty chair had said was Jimmy Stewart (without the accent" to a "T" and THAT is what Clint was parodying. Go to You Tube and watch his speech and watch some of Jimmy in Harvey. Perhaps Clint should have said, “I have this empty chair here to represent barack “Harvey” obama"... for some of those that are a little slow on the take.
LLS