Michael Bloomberg
Critics may deride him as the city's Nanny in Chief, but that hasn't deterred New York City Mayor Michael Bloomberg from his aggressive public-health campaign. After prohibiting trans fats in restaurants and banning indoor (and even some outdoor) smoking, Bloomberg, 70, followed up with another controversial ban, passed in September, on the sale of sodas and other sugary beverages in sizes larger than 16 oz. At the national level, Bloomberg pressed the case for gun control, an issue largely ignored by the presidential candidates, after the Dark Knight movie-premiere massacre in Aurora, Colo. But Bloomberg's 2012 may be best remembered for his high-profile role after Superstorm Sandy. The hurricane's destruction prompted Bloomberg, who until then had remained neutral regarding the presidential race, to endorse Barack Obama just five days before the election — and to spotlight, as his rationale, another issue he feels the political process has foolishly ignored: global warming.