#there are pre- and post-DITF issues of Batman and Detective Comics where it comes up!

[nyerusnova]

Going to toss in my two cents here real quick but I firmly believe: Batman cannot kill, and there cannot be exceptions to that rule, or else the entire ethos falls apart.

Like trust me, Bruce Wayne has personally contemplated killing people multiple times, and has come very close to it before. It is not that he doesn't ever want to kill, but he knows that the Batman cannot kill. Because if he does, then the hope of Gotham is lost, nevermind elsewhere at large. People will have no reason to believe in their heroes, when their heroes decide to play judge, jury, and executioner. Even if we (and diegetically, many characters) know that certain criminals/villains will never change their ways and only want to cause more harm, Batman especially cannot go that far.

Other heroes (most notably Wonder Woman) do fight for more "pragmatic" reasons, and thus will take a life when they deem necessary. But Batman is not one of them. What he's fighting for is not just harm reduction, it's to show people that goodness and justice can prevail. And you might not agree with that ideology, but that's still something important to exemplify -- both in-universe and out.

If he kills, then even ordinary people will have no reason to trust him. Batman goes from a symbol of hope to a yet another symbol of fear for the people of Gotham.

And no, the Joker of all people is not an exception -- he is in fact a major point/reason for the rule. Could maybe other people kill the Joker? Yeah, sure. Narratively boring in most cases, but it would take out the trash. However, of anyone in that universe, it absolutely cannot be Batman. Because that is exactly what the Joker wants: chaos! That's why him being taken out by other people isn't as interesting, because to him his own death is largely meaningless. What the Joker wants is to prove that anyone can be pushed to that edge, including someone as righteous as Batman. If Batman kills him, then the Joker has successfully destroyed the hope of Gotham. He wins. And that's not something Batman can ever take back or recover -- it's game over.

As for Jason: keep in mind that Jason has had chances to kill the Joker himself. But he hasn't, because he wants Bruce -- Batman -- to do it. It presents an interesting quandary, because with this, Jason isn't thinking about the big philosophical picture that Bruce is. (If you want a generous take on him, he is more "pragmatic" about harm reduction. Killing the Joker would save lives, and he wants Bruce to see that. A more realistic take is that it is selfish desire for vengeance as the main driving factor. I won't get into his characterization it now because it's a mess that deserves 10 posts on its own.) At the end of the day, what he really wants for his father to choose him, over his own ideals. And he's not even entirely wrong in wanting that. Fundamentally, that's what makes the conflict between them so interesting. Bruce cannot put his children or loved ones first; he is a hero first, and everything else second. That's the tragedy in being a hero. That bears it's own meta, imo.

In short, Batman's no-kill rule has persisted in comics for decades for a good reason.

I'm actually curious now to find out what the common consensus is so