Bush in paradise

Einstein dies and goes to heaven. At the Pearly Gates, Saint Peter tells him :
- You look like Einstein, but you have NO idea what some people will do to sneak into Heaven. Can you prove who you really are ?
Einstein ponders for a few seconds and asks :
- Could I have a blackboard and some chalk ?
Saint Peter snaps his fingers and a blackboard and chalk instantly appear. Einstein proceeds to describe with arcane mathematics and symbols his theory of relativity.
Saint Peter is suitably impressed.
-You really ARE Einstein ! he says. Welcome to heaven !

The next to arrive is Picasso. Once again, Saint Peter asks for credentials. Picasso asks :
- Mind if I use that blackboard and chalk ?
Saint Peter says :
- Go ahead.
Picasso erases Einstein's equations and sketches a truly stunning mural with just a few strokes of chalk.
Saint Peter claps.
- Surely you are the great artist you claim to be ! he says. Come on in !

Then Saint Peter looks up and sees George W. Bush. Saint Peter scratches his head and says :
- Einstein and Picasso both managed to prove their identity. How can you prove yours ?
George W. looks bewildered and says :
- Who are Einstein and Picasso ?
Saint Peter sighs and says
- Come on in, George.