Although sending a bus off the road might seem like small potatoes these days, the amorality of The Joker's actions chilled me. Even as a kid, I knew it would take a lot for someone in the real world to emulate The Batman - they'd need an endless supply of money, technology ahead of what even the highest levels of law enforcement employed, the kind of physical training that only a handful of people in the world could provide, and a indefatigable spirit. And even with all that, anyone who really tried to be Batman would get their ass handed to them. But on the other hand, it would take very little to be The Joker and make it work - just a willingness to cross lines that others wouldn't and, as a child, that thought alarmed me. As I said, it had never occurred to me prior to this that anyone could kill randomly, without purpose (apparently I lacked imagination!). It introduced an anxiety that was new to me - that is, how can you defend yourself against someone who would kill you just as easily as they would the person next to you? How can you anticipate the sort of plans that a lunatic would put into play to murder people that he's never met?
So as a character, The Joker really unsettled me - but his incarnations in TV shows and movies have always been another story. I gave Caesar Romero a pass on his Joker from the '60s TV show but Jack Nicholson's wasted opportunity was almost enough to make me angry. Before The Dark Knight, I thought the closest to the "real" Joker that fans would experience outside of the comics was Mark Hamill's expert vocal performance in the Batman cartoon series of the '90s. But thanks to director Christopher Nolan and actor Heath Ledger in The Dark Knight, for the first time on film, The Joker has earned his high-ranking place as Batman's arch-nemesis.
Rather than take the character's historic popularity for granted, Nolan's ambitious screenplay (co-written with his brother Jonathan) has put The Dark Knight in the front-running to be considered the definitve Batman/Joker tale. As an equal to comic tales such as The Long Halloween or Batman: Year One, The Dark Knight makes us understand how The Joker can get under Batman's skin in a way that villains like Killer Croc, Mad Hatter, or even A-listers like The Penguin and The Riddler can't. He isn't just a slippery character, he calls Batman's whole crusade into question.
Ledger's performance not only leaps past the hammy quality that deliberately snuck into even Hamill's Joker at times but he burns through the cliche of the 'scary clown', which always was the hook to previous portrayals of The Joker. In the history of the comics, Ledger's Joker reminds me most of the Joker as depicted by artist Neal Adams and writer Denny O'Neil as seen in 1973's "The Joker's Five-Way Revenge" (Batman #251) in that as drawn by Adams, The Joker was no longer a costumed super-criminal, instead he just dressed in a distinctive, but contemporary, fashion (after Adams' run, The Joker was returned to his familiar pinstripes). And as written by O'Neil, The Joker was returned to being the murderous psychopath that he was in his original '40s incarnation and the gimmicks, pranks, and props that had become so outrageous during the '50s and '60s were done away with (no more giant jack-in-the-boxes or rocket launching Pogo sticks) and his methods were brought back to street level (like Ledger's Joker, the things he likes - such as exploding cigars laced with nitroglycerin - are cheap). "The Joker's Five-Way Revenge" was a model for how to make The Joker 'real' and The Dark Knight is the first depiction of The Joker outside of comics to accomplish that with the same success.
I hope that Ledger's death won't shut the door permanently on The Joker in live-action. Although it's impossible right now to imagine anyone matching his approach to the character, his performance does prove that in the right hands, The Joker is far more than just a giggling buffoon.