With a revamped message and a significant TV presence here, Rick Perry is hoping to revive his disappointing presidential campaign with a surprise finish Tuesday. But even as they hold out hope that Perry can find a way back into contention, some of his advisers have begun laying the groundwork to explain how the Texas governor bombed so dramatically in a race that he seemed to control for a brief period upon his entry in August. Their explanations for the nosedive come against the backdrop of a campaign riven by an intense, behind-the-scenes power struggle that took place largely between...