Julie Roehm’s legal and public-relations strategy may seem hyperaggressive. Besides suing Wal-Mart for wrongful termination, the former marketing star has accused its top officers of violating the company’s conflict-of-interest rules. Now Roehm has hired Michael Sitrick, whose Los Angeles public-relations firm is known for going atomic on opponents, using “truth squads” (which dig up alleged inaccuracies in the media), “wheel of pain” tactics (negative publicity to quicken settlements), and high-profile journalists (who write profiles).