It is, at least initially, a question of style. The Devil is always preternaturally cool. The Devil is always powerfully sexy. He is the grand, sympathetic villain full of potent aura, seductive force, excellent badass cowboy boots made of forgotten dreams and kinky sex and extinct pterodactyl.
Bush is, of course, never cool. Bush isn't even in the same room as sexy aura or charisma. Bush ambles, stutters, gropes German chancellors without warning, speaks with his mouth full of bread and spits the crumbs on the jackets of foreign leaders. Bush's cowboy boots are made of petroleum and Elmer's glue and cheap cowhide from depressed, hormone-injected Texas cattle. The Devil wears Prada. Maybe a little Dolce. Bush wears tighty-whities and plaid. It is not an insignificant distinction.