But the apparent relative ease with which Joker does this is what makes the Dent storyline strike so close to home: The film makes us realize that we, as humans are limited, and that our capacity to be good is subject to the vagaries of fate and whatever the hell else decides to destroy what we love.
Dent is not just a proxy for hope, he’s a proxy for us as well, reminding us of the duality that lies within each of us.
In our society, what exactly constitutes cause for alarm? What do people do when they are put in the worst of situations?
What would you do if you were given the ultimate power over someone else?
The Joker is unpredictable and can’t be reasoned with, nor does he have any broader goals except to create chaos and destruction.
When people violate this personal space, the results can be terrifying.
He becomes hunted, making people believe that he cannot be controlled, that he has lost all respect for societal norms and the rule of law.
As Gordon realizes he needs to blame the murders on Batman, he acknowledges not only the need for society to push their fears onto something, but their hopes as well (which he allows them to do by preserving Dent’s good name).
In a similar fashion, the Joker upends the genre conventions of a villain in that he has no inhibitions and refuses to hew even to the ultra-basic moral code of criminals (see: the opening scene).
When a character has no values that you as a viewer can relate to and hold on to, the results are extremely disorienting.