"Where Mitt Romney is obedient and cautious, Rick Perry is bombastic and spontaneous. If they had attended the same high school, they probably would have hung out at opposite ends of the hallway. Their relationship today is said to be frosty, if there is one at all.
"'In every single possible way, they come from different worlds,' said Republican strategist Alex Castellanos, who advised Romney in his 2008 race but is neutral this time. 'You can see the playbook pretty clearly here: it's populist against patrician; it's rural Texas steel against unflappable Romney coolness; conservative versus center-right establishment; Texas strength versus Romney's imperturbability; Perry's simplicity versus Romney’s flexibility.'"