For example if they regret it right after and manage to revive them afterwards. Can you then get charged and imprisoned for first degree murder? (assuming it was premeditated) After all, you technically murdered someone. If not, what would you be charged with? Just something related to what you did? Like assault.
I think that if the victim survives the event (as in, does not require the services of a medical examiner or undertaker), it’s only considered “attempted murder”. Please note that I am not a lawyer, police officer, medical professional, or any other relevant profession.
I can’t imagine this being treated any differently from just not killing them when you tried the first time. I agree with “attempted murder.”
If they aren’t dead it isn’t murder.
This reminds me of people saying that they were “electrocuted” when of course they’d be dead if they were.
As others have said, it would only be attempted murder.
Attempted murder can certainly earn you plenty of prison time as well although it may be less than you would have gotten for a successful murder and you wouldn’t be eligible for the death penalty where applicable. I suppose the reasoning for that is that treating the crimes exactly the same would give would-be murderers an incentive to complete the murder once the attempt was made. In this case, the attempted murderer is still probably better off if he revives the victim than having to face a true murder conviction.
I’d have to think that “The person I’ve been accused of murdering is still alive” is pretty much the gold standard of legal defenses against murder.
Now if you try to kill someone, change your mind and perform CPR, and they survive, but die the next day in the hospital due to the injuries they suffered during the murder attempt, it’s still murder.
Exactly - and if you are sentenced to death - are pronounced legally dead - then found alive in the prison morgue - they still are going to execute you.
Legally dead is not factually dead 
No, you didn’t. It isn’t murder until the victim is dead. If he can be revived, he wasn’t quite dead, yet.
He may only be mostly dead.
Best username/answer combo ever.
Need answer fast? Better to revive them.
This presumes that it is impossible to revive someone who is already dead. In other words, if it presumes that if a person is declared dead, and is then revived, then the declaration was in error.
However, this depends on how one defines “death”. If one defines death as the loss of spontaneous breathing, or brainwaves, or whatever, it might be possible to revive them despite being truly dead, in which case the OP’s question is valid.
With all due respect, Cheshire Human seems to include “unrevivable” as part of the definition of “death”, but others might disagree.
Yes, I do. Any medical or religious or legal definition that doesn’t include “and he didn’t come back” as part of the definition will inevitably lead to ambiguities like this. Legally, “and he didn’t come back” is an implied requirement for a murder charge.
eta: If you come back from it, it means you were just in that grey area where we can’t measure ‘nearly dead’ and distinguish it from ‘certainly dead’. We just don’t know where the line is, and so use medical definitions that usually work, while recognizing that they are sometimes wrong.
Just to clarify, I personally agree with Cheshire Human regarding legal and medical definitions, because they have to deal with the very practical consequences of death. But I think that religions deal with death in an entirely different way, and they could be entirely okay with the idea of saying, “Well, yes, he’s dead for now, but we’ll see…”
Prosecutor: “Please look around the courtroom. Do you see the person who killed you?”
Witness: “Yes! It’s him! The defendant! He killed me!”
Prosecutor: “The state rests.”
I don’t think so.
Yeah, once you bring up religious/fantasy/sci-fi concepts you end up with weird situations where the real-world rules don’t apply. Like someone testifying that he was murdered 15 years ago by someone in an earlier incarnation, or a ghost pointing out his murderer in court, or someone having been murdered but the act of murder erased via time machine, or “he was murdered but we had a backup copy”.
Well, that’s where we differ, then. Any time a religious person comes to me and says “NDEs prove there’s an afterlife, and give us evidence of what it’s like”, my response is “NDE means exactly, and only what it says: Near-Death Experience. Just like doctors and lawyers include an implicit ‘and he didn’t come back’, because they can’t define it in a more specific, unarguable, and final way, I, too, insist on that implicit requirement. If the guy came back, he wasn’t dead, period, and he has nothing at all useful to say about ‘the afterlife’.”
Hmmm. So let’s look at the classic common-law definition of murder: the unlawful killing of another human being with malice aforethought. (Thanks, wikipedia; since all of my outlines were done in OneNote, I can’t access them. I feel Prof. L’s definition was a bit longer, but anyway.) The critical element here is “killing.” Killing is defined as causing the death of. As I read it, if someone was, in fact, medically dead, the element is satisfied, regardless of whether they are later resuscitated.
This is what I’d argue on the prosecution side. On the defense, you all have pretty much covered it. Plus–definitely want to insist on your right to a jury here, as they’ll be more inclined to be persuaded by the sight of the victim sitting there breathing behind the prosecution table in the first row. 
Huh? Execution for attempted murder, right? I mean, the legalities have to be, well, legal.
If the victim revived after the execution, is there a way for a judgement or sentence be amended? I don’t mean in the sense of “we’re sorry, we got it wrong,” but…well, yeah, a correction to the record.
That must happen all the time in ordinary court cases.