The idealism and lack of perspective in this thread is nauseating. Can any of you provide an answer to non-lethal options beyond "anything but a robot"? And the amount of excusing the guy gets for having shot up a city block is incredible. You point a firearm at innocents, you've lost your guarantee to life. Is that so hard to understand?
We are a country of laws. When a cop takes a life, they put the law into their own hands and decide that they are above it. They are no longer enforcing it, they are deciding it. If, after a trial, the death penalty was handed down then so be it.
If we can't guarantee that right to everyone, regardless of how horrible the actions they took were, then the right to it might as well not exist.
That said, there are situations when the police are justified in making that decision, when there is a clear public harm that could take place should they not act. That said, whenever they do make that decision, they too should have to face a trial where they can provide evidence that their actions were the correct ones and were thus justified. If they weren't, then they should be punished accordingly.
It's those last steps that never seem to take place, which effectively place the decision to kill into the hands that are not given judicial justification for that right. The police need to better justify their use of lethal force, that they haven't been able to do so in case after case after case, yet they've faced very little if any punishment for those failures, undermines the fabric of the laws we put into place to protect us.
It's incredibly complex, of course, so trying to put it in incredibly simplistic terms does little to help anyone nor does it advance the debate that needs to take place.