Bill Clinton is getting nervous.With polls showing Bernie Sanders ahead in New Hampshire and barely behind, if at all, in Iowa, the former president is urging his wife to start looking toward the delegate-rich March primaries — a shift for an organizing strategy that’s been laser-focused on the early states.Bill Clinton, according to a source with firsthand knowledge of the situation, has been phoning campaign manager Robby Mook almost daily to express concerns about the campaign’s organization in the March voting states, which includes delegate bonanzas in Florida, Illinois, Ohio and Texas.Many Clinton allies share the president’s desire for more organization on the ground; they see enthusiasm that’s ready to be channeled, but no channel yet in place.