Can Batman be able to operate if he broke his no killing rule

[Soubhagya]

For Batman to work just as concept (at least one taken more seriously), the GCPD has to be out of their depth. Else he becomes a luxury, not a necessity. For his relationship with Gordon, he can't take the law into his own hands. Ultimately, he has to bring criminals (super or otherwise) to justice, not deliver it to them. Regardless if killing the Joker is the morally correct thing to do, it's not for Batman to decide. None of this is even taking into account his own psychological need to not kill, which is a fundamental aspect of who he understands himself to be. If Bruce kills, he ceases to be the man who became the Bat. He desecrates everything he stood for. It calls every action until that moment into question. Why now?

If he was going to kill, it would have started a long time ago. It's too late now. Personally? I hate making Bruce into an overly dark avenging type character. That's a quality of him for sure, but he's also a good man at heart and not just some psycho one percenter punching poor people off their meds. He has his line. Criminals fear him because being in a full body cast is not good for them in their line of work, either for being able to pay up to whoever they need to or their credibility. It also really freaking hurts. He's plenty scary. You don't have to be afraid for your life to be terrified. Sometimes dying is a lot less frightening than living with the repercussions of one very bad day. Hell, many Batman stories would attest to that alone.

Moreover, on a meta level, most of Batman's rogues are too big for reality to set in. Someone, either inmate or cop, would really just have plugged the Joker and gone down as a martyr by now, but he's just too profitable a concept for DC to retire.

tl;dr

Killing breaks Batman. That's just not really what the character is about.

Some stories say that if he kills once he is changed forever. This is not how it works. Sometimes killing becomes necessary to save lives. That kind of killing where there was absolutely no other way to save lives does not corrupt.

Yes killing next time would be easier but not that easy that he would give up everything Batman stands for.

As you pointed out and i agree Batman is a necessity. He is required because the system does not work as effectively as it should. Batman breaks the law in order to safeguard it. Yes he does a lot of illegal activities: child endangerement, breaking and entering, etc. But all this he does because there is no other way to bring Justice in Gotham. This is how the stories are written. Thus, he is law abiding even if apparently breaking it.

Killing somebody may be Joker or any criminal out of his own will is a step too far. He catches criminals and delivers them to the law. A lot of them are mentally ill. He helps them to be cured. His violence is his compassion. It is necessary because it is like this in Gotham where best way to fight crime is to dress up like a Bat. But there is kindness and altruism in his actions. Not to punish but to cure. To make Gotham such that others will not have to suffer like how he suffered.

Thus as soon as he starts killing regularly he is no more Batman. He may be able to operate without GCPD. But he has become an executor. A Punisher who punishes crime. Batman is no Punisher. He is like a special police force who does things which the regular force cannot. In theory an outlaw but in practice a member of the police.

Thus i say if he kills once or twice out of compulsion and not out of choice he can operate as Batman. Gordon will help him so that murder charges don't fall upon him and that Bat-Signal stays. Gordon knows Batman is a necessity.

But when he starts killing carelessly then there is no Bat-Signal. He is not the Special police force. He was an outlaw officially yet working for GCPD. But now he becones an outlaw in theory and practice.

By his wealth and connections he maybe able to operate for sometime. But he is not the only one. There are others: Nightwing, Batgirl, Robin, Batwoman, Red Robin and more. Even Cassandra Cain The Orphan is a more dangerous fighter than Batman. And outside of his family the Justice League. As a criminal he would be brought to Justice by any of them. Gordon will try to contact someone who can bring Batman to custody. A killer Batman is just a supervillain like others.

[Robanker]

I can't say that I disagree with any of this (except the bit where you say that Batman shouldn't take the law into his own hands when literally everything he does is taking the law into his own hands), but that is not the discussion we're having.

This isn't a "should Batman kill?" thread.
This is "Batman kills. For whatever reason he just does. Period. Can he still be a succesfull rooftop vigilante?"

Then, frankly, no. I don't think Gordon and the GCPD would tolerate him. He'd be hunted.

I agree Batman takes the law into his own hand to some degree, but that's the one place he never really will without ceasing to, well, be Batman. He'd have to adopt a new persona since willfully killing also kills Batman. Essentially, he digs two graves at the end of that path.