Character Analysis
Harvey, Harvey, Harvey Dent. What's there to say about him except that he so perfectly embodies his own phrase?:
HARVEY: You either die a hero, or you live long enough to see yourself become the villain.
That's pretty cold, Harv, but you gotta admit: no one goes from good guy to bad guy like you do.
And that's kind of the point. At his worst incarnations in the comics, Two-Face was pretty goofy: committing crimes based on the number two, like robbing the 2nd National Bank. That wouldn't do for Nolan's down-and-dirty Batman, so he's been reinvented here with a focus less on the literal and more on the symbolic. Harvey really does seem to be two different people in this movie. At first, he's the heroic District Attorney, ready to stare down mob assassins in the courtroom even as he's sending up their bosses for life.
Everyone loves Harvey. Even Bruce, whose squeeze Harvey's taken, is ready to give up being Batman because he thinks the DA is just that darn cool.
Then, of course, there's the other side. Once the Joker drives him over the edge, Harvey Two-Face is everything that Harvey Dent wasn't: violent, erratic, relying literally on chance to make all his choices, and ultimately a danger to children and other living things. Like that coin he constantly flips, Harvey has two distinct and opposite sides, and the tragedy of his character is that the dark side ultimately gobbles up the light.
But things in Harvey's psyche aren't quite the neatly split Oreo they might appear to be. There's always a little bad in Harvey's good, a touch of shadow in the midst of his light.
He's a bit of a sneak for starters. He doesn't mind bending the rules when it suits him; minor ones to be sure, but certainly notable. Look at how he pulls strings to get Rachel into that swanky restaurant, for instance, or how he knows that his convictions will be overturned in 18 months, but goes ahead anyway because it will buy the cops the time they need to do some real good. Sure, he has noble goals there, but the law he claims to uphold isn't always at the top of his mind.
Then there's his temper. Sweet merciful McGilligutty, is his cork in tight; when it pops, look out. He keeps it more or less under control, but every now and then, you can see it slip out. Look at him bellowing "YOU CAN'T GIVE UP!" after Batman says he needs to turn himself in. His voice is raspier, his forehead vein is throbbier, and suddenly that squeaky clean DA doesn't look all that different from the monster he becomes.
So clearly he's got some anger issues, which finally overwhelm him as Two-Face.
You can see the roots of that in Dr. Jekyll and Mr. Hyde (which Batman's original creators Bob Kane and Bill Finger based the character on), and that always makes for a cool character. It's an easy and very slick way of talking about everyone's dark side, and how the better angels of our nature constantly battle with the dark side. Harvey's stuck between those two halves. Unlike Batman, who ultimately stays on the heroes' side, and the Joker, who's rotten to the core, Harvey stands on the middle of a great big spiritual balance beam.
That makes him closer to us normal folks than either of the other two. Most of us try to be good and want to be good, but are tempted to do bad because we get angry or scared or some combination of the two. Harvey's us in the story, at least before he falls. After he falls, he's much more of a cautionary example: warning us folks in the real world who think that our anger and our fear can solve our problems.
We see that not only on an individual scale, but on a social scale as well. As a society, we're constantly asking ourselves—debating, arguing and in some cases screaming at each other—about whether we're doing the right thing, about whether we're keeping our country safe, about where the line between good and evil is, and if we'd even know that line if we saw it. That's true for a nation as much as plain old folks just doing their best to get through life. Harvey, a public official who's supposed to represent all of the people, makes the perfect representation of that. Have we fallen the way he has? Or will we stick to the light side and keep that manky evil from scabbing up our face? Harvey made the wrong choice, but we don't have to… if we take a little wisdom from his example, that is.