Aand we're back to the fact that it's ridiculous that no one has yet so much as attempted to kil the Joker yet.
It's been established that Batman is about the only one who can actualy catch the Joker and make it out alive. The authorities cannot kill him within the letter of the law after he's been apprehended. Therefore, the only reason who can actually get away with killing the Joker is Batman, making him most responsible for the Joker running around.
One thing I WILL fault him for is that story arc where the Joker almost finally gets sent to the electric chair, albeit ironically for a crime he did not commit. This is not good enough for Bats, so he goes on to actively protect, exonerate and get the Joker released. Because "there can be no short-cuts" and now the Joker "will have to live every day knowing he's in Batman's debt".
I'm sorry, but...WHAT?! He was finally convicted, sentenced and out the door toward the injection and Bats saves him because he wasn't sentenced for one of the crimes in his long and terrorizing career he DID commit?
I think that was the point where I got turned off Bats' M.O. Permanently. Damn right its his fault that a mad serial killer is on the loose.