Fluffs are no-doubt creaming their beanies over this "sheriff" line. More disturbing evidence of Bush's cowboy delusion etc.
But what exactly was Dubya's intention? I suspect that as well as communicating a strong sense of allegiance he was being mildly humorous - as he is wont to do occasionally.
Take the line: "There's nothing deputy about this relationship." It's kind of colloquial, slightly self-parodic. Has a bit of nuance, light and shade - which is why retarded, credulous fluffs can't process it and immediately go spacko.