This will, hopefully, be a very participative post.  Spoilers of a sort ahead.

I have two points to contribute.  Obviously it was a brilliant film on many levels, I hardly see them all.

First, I think the Joker (played to perfection) expresses to Two Face, in the hospital, what Martin Sheen suspects of Marlin Brando in Apocalypse Now: no methodology.  The Joker makes clear that social structures all entail intimate and extensive planning with very high costs to a sense of morality and universal justice.  The downside to these controls is that our expectations create vast dehumanization.  He points out that endless numbers of people can die in a war declared by Congress, but if one hospital is threatened, a whole city loses its collective mind.  As he says, "madness is like gravity, all it needs is the right push."  Here, I think it becomes clear that, even though he says he only wants to undo the planning, he's only replacing it with his own planning, thereby undermining his purpose -- not that he cares.  He personifies the unbalancing of an equation -- the envelope pusher.

However, whereas social change is supposed to be a gradual process, the Joker has little patience and attempts to insure that we see it all at once, and thereby understand it.  There are many scenes of destroyed buildings which should remind us of The World Trade Center.  Those images coincide so that we can, as Americans, re-experience those horrors from a more rational perspective.  Through this film, we are given the gift of re-examination.  We can begin to understand the extraordinarily dynamic and boundaryless force behind destruction, and compare that to the oversimplified "post 9/11" worldview which settled like 1's and 0's. 

Second, towards the end, Batman says that Gotham deserves more than truth.  Clearly he is not referencing some transcendent "Truth."  He is pointing to the "truth" of events: specifically Two Face, the city's D.A. and poster boy, turning into a monster for the sake of vengeance.  Batman makes a move, more like Saul Olinsky than Machiavelli.  Given the circumstances, the "truth" of events will mean victory for the Joker.  The reasoning for a lie is that the city of Gotham will be disheartened and feel hopeless without it.  If the Joker can reach inside the very best citizen of Gotham and turn him into a monster, no one else stands a chance.  Now, intellectually, things get heated. 

Olinsky taught that we cannot stand back and try to be 100% moral in every single decision, like the Kantian Categorical Imperative.  Standing back, necessarily, means not moving forward.  Olinsky would have it that, we have our end in mind, and draw from the situation, making the best possible decision, given our options.  Batman does not hesitate -- Arthur Dent would have.  Batman is not a hero, Arthur Dent was.  This is what makes a White Knight different from a Dark Knight.  The Dark Knight fudges, taking the blame for Dent's insanity, so that the people can still believe in themselves.

I cannot help but think of FISA.  Some bloggers believe that any movement to the center is Wrong.  Mr. Obama however follows the blueprint left by Olinsky.  Holding the end in mind, we must make the best decision, given the situation. 

Apparently the writers also thought of FISA, or telecommunications and oversight, at least.  The triangulating device that Bruce gives to Lucius, which uses the citizens cell phones, is clearly symbolic of domestic spying.  Now, in this circumstance, the benefit far outweighs the cost.  Sacrificing privacy for the sake of several hostages is worth it (unless you hold the Kantain Categorical Imperative). 

I don't believe this administration's use of FISA is analogous to what happens in the film.  After all, Bruce tells Lucius how to destroy it, with the signing of his name, once their mission is complete.  The point, however, is that Lucius does not destroy the device the very first opportunity he gets.  And yet, it still gets destroyed. 

I hope this image lays to rest any lingering debate over FISA.  A picture always helps.