Jeff Spross and Zack Beauchamp try to decode it:
The best way to understand Nolan’s political argument, such as it is, is to step away from contemporary political disputes and pick up an old essay: Judith Shklar’s "The Liberalism of Fear." Shklar argues that the most universally acceptable moral foundation for individual rights and democracy isn’t any particular religious faith or abstract moral theory – rather, it’s that we’re all scared. We’re scared of the unchecked power of both our fellow citizens and the state, and want a political system capable of reigning in both. As she puts it, "liberalism’s deepest grounding is in place from the first, in the conviction of the earliest defenders of toleration, born in horror, that cruelty is an absolute evil, an offense against God or humanity." Fear, of course, is the emotion that most suffuses the Dark Knight trilogy.
Earlier Dish on the ideology of Batman here.