A lawsuit too far: In a nation with an undisputed child-obesity problem, should public-policy institutes study the causes? Absolutely. Should they disseminate their findings far and wide to inform parents, school officials and paid caregivers of the triggers to overeating and the dangers it poses? No question. Should the Center for Science in the Public Interest, a self-styled public-health watchdog group, sue McDonald's restaurants because they slip toys based on the latest "Shrek" movie into their Happy Meals? A big fat no, unless the center's objective is to persuade McDonald's to avoid promoting healthy substitute meals out of fear of appearing guilty. Instead of paying lawyers to sue McDonald's, how about diverting that money to fund a public-service advertising campaign, or send specially trained nutritionists to schools to spread the anti-obesity message to food-service managers?