Way too much stuff was exploding or being ridiculous during the movie itself so I had to reconstruct what it was trying to do afterwards. Basically, a utilitarian moralist (Batman) came to realize that despite the short term effectiveness of his good-doing efforts they were having a bad effect on others, who couldn't handle utilitarianism conceptually and were reacting to the challenge of seeing it work by stereotyping it harmfully and then acting on those wrongful beliefs.
The important initial examples of how people got it wrong:
1. The copycats: the ends only justify the means if they're reached, and the copycats don't realize they lack the skills to reach the ends Batman, an obsessed kung fu master billionaire with a shattered personal life, can.
2. The mob: used to a justice-based status quo where loopholes or shadow areas created by rigorous application of the law, they were thrown for a loop by Batman, but came to assume his utilitarianism could be subdued by their killing enough people--Batman's undermining the rule of law making them throw out the few rules they played by as well (hence unleashing the Joker). All you have to do to neutralize someone acting for the greatest good of the greatest number, they reasoned, was threaten the worst harm to everybody. Batman would have to capitulate according to his own principles, thereby restoring the rule of law and in turn its protective shadow over organize crime.
The movie refused to go in the direction of Batman simply destroying the mob--which could have led to further reprisals, with surviving mob members just killing anyone they saw or poisoning the water supply or something. All of which may be a bit closer to the actual terrorist/counterterrorist dynamic of recent years (summer blockbusters are getting increasingly terrorism, Iraq & 9/11-obsessed--you'd think escapism would be preferred?), well treated in Munich.
Instead, Batman's rule of never killing is emphasized. Perhaps he's seen Munich, and has adopted this principle of justice for utilitarian reasons. At any rate, the thing that goes wrong with the Mob's plan is that Batman ultimately refuses to give in, and the fire they set to compel him to gets out of their control and threatens their own interests as well (the money-burning scene). He is another misunderstander of Batman:
3. The Joker: feels indebted to Batman for proving that the rule of law doesn't work, but is convinced Batman's way can't hold things together either, and that therefore, since no ethical approach is waterproof, none should be attempted. The Joker speaks of killing as the only way to honestly know them--he feels mass killings will lead to chaos which will lead to fear, which is presumably the reaction of honesty to the truth of the human situation that he wants to see. He breaks people to prove to them that they are breakable and therefore ought to be broken. (This is too close to the Judge: the Nolan brothers owe Cormac McCarthy a lot of money (also William Styron).) His misunderstanding of Batman's utilitarianism consists in his assumption that it has something to do with purity: Batman doesn't have a defined idea of the good so much as a native sense of which direction it's in, and therefore can always fight for more of it (though, as we'll see, Batman accepts that the human imaginative attachment to purity, and the consequent need to banish impurities, is a necessary resource for securing a good society). The people on the boats have no idea what they're doing, but they can't abide the idea of killing people. Morality's basis is a human allergy to evil, which the Joker and the Burmese bandit simply don't have--and therefore apparently are confused and provoked to see others have.
With his no killing rule, they almost get Batman to reveal himself and thus abandon his power. Harvey Dent stops it from happening. Dent is the representative of justice but, exactly like the copycats, sees and envies the effectiveness of Batmanian utilitarianism. The movie insists that only Batman himself, and perhaps his employees like Gordon and whoever Morgan Freeman was playing, has the proper knowledge to work toward the good outside of a framework of principle. When Dent tries to go out of bounds, he's immediately inclined to torture (bad torture, in the movie's terms, i.e. leading someone to think he'd die if he didn't talk, as compared to Batman beating the Joker to a pulp to get information but scrupulously informing him he wouldn't kill him)--and perhaps even to kill. The implication is that no one can actually embody justice consistently--and yet if you're not Batman it's crucial to try, and therefore crucial to believe that someone can (more money for McCarthy, this time for the Cities epilogue?). Batman does his best to keep Dent on the right track--w/ advice, funding etc., but Dent continues to aspire to assessment of utility. He lies about being Batman without knowing all the angles of where that will go. Batman is unable to protect him. Dent survives but loses internal locus of control, assumes the universe is unjust and cannot be fought, his coin becomes emblematic of an essential randomness he feels he must extend and prove to others (eleven dollars owed for No Country now). The Joker desired to create chaos and has done so rather literally.
Ethical drive without an ethical basis drives people mad: into denying the existence or appropriateness of ethical drive, into arbitrary manufactured ethical bases--defending which kills access to logic and undermines or compromises the very impulse toward the good that the manufactured principles were intended to protect. We don't see the dark side of "order" in this movie, except for how its blind spots permit the existence of crime, predominantly because the movie's about what happens when old orders decay. Batman ultimately decides to restore the old one with a lie, by propping up a false, deceased messiah. The audience is supposed to admire him for not caring if he's hated and hunted and not question the various fairly infuriating implications of the nobody-can-take-the-truth message. Batman's setting up a "white knight" who holds to ideals of justice, but is himself being set up as the only human capable of the total altruism and omniscience (his magic magic eyes) required to make utilitarianism viable.
Because the reason thoroughgoing utilitarianism is infuriating is that it has to rebase itself at every point--there are no rules of conduct except those dictated by the situation, which means you always have to understand every situation, or somehow understand how much of each one you don't understand (which would require understanding that portion!). Batman accepts Morgan Freeman's skepticism that even he should pretend to be able to handle that kind of role, which is ultimately why he's trying to pass the torch to Dent, alive or dead. There's also a human cost he's tired of paying. The mastery of every context is only possible if one stops being a person (in comicbookland, and simply doesn't happen outside it).
Why aren't ad hoc guesses and skepticism good enough? Because we're in comicworld here and the stakes are unreasonably high. Evil's flowing in all over. Implication being that that's happening now, as the relentlessly highlighted, if inexact, parallels are intended to suggest. I think my main problem with the idea content here is pretty close to my issue with Pan's Labyrinth. Not everything is wired to explode, and not enough things are exploding to justify our treating everything as though it were, even though we don't know which things are wired--and yes, some are wired.
I should post some of my Julius Caesar essay from a year or two ago. Shakespeare's dazzling with all of this, with more.