Stupid bullshit …

… is it always when someone asks about some legal stuff without saying what country’s/region’s/city’s law he is interested in.

Everybody here is kinda right, but there are other factors to consider, and the net result is that it’s usually not a case worth bringing.

The “Impossibility” defense says that in most cases, the “factual” impossibility of committing the crime is not a defense, but taking an action that is not a crime is a defense, and if raised must be proved by the prosecution. Even with “Factual,” the line gets muddy (the article cites a person whose appeal won after they were convicted of poaching after shooting a stuffed deer). Many jurisdictions have a “reasonable person” standard for that as well, where if the act is the sort of thing that might normally be expected to result in a crime (the most infamous case is two US military personnel who thought they were raping a passed out woman, but really she had died from a heart attack) then you get no benefit, but if no reasonable person would believe that their action would do anything, then it’s more likely to succeed. To answer one of your questions, being told the button sets off a bomb would be more problematic for our hypothetical asshole than being told it “just kills” somebody that would be a bigger problem than a Death Note notebook, but it’s not a simple yes/no.

So anyway, this then raises some questions. Was this button setup convincing? Who did the convincing? Why did they do so? Other defenses might arise out of these conditions: e.g. they were told that pushing the button would save a bunch of other people, trolley-problem style, or it was the police egging them on and telling them they needed to for XYZ good reason. Many of them will turn on the defendant’s thoughts, so in any jurisdiction where they are not obligated to testify (e.g. the United States), our very interesting defendant simply doesn’t, and their attorney argues that there’s reasonable doubt they thought the button would actually do anything.

Add on top of this prosecutorial discretion. A prosecutor knows all of this, and knows this is a loser of a case, so apart from truly bonkers hypothetical, they will not bring it.

TL;DR: By the letter of the law, very probably yes, but no one will ever get convicted for it.

IANAL. In the USA, the majority of US States adopt some definition of murder based on the age-old definition from English common law. But each state modifies the definition to include or exclude things, to the point that discussing even just a single state’s definition would be a mini law course. However, some generalities can be drawn using just the age-old definition.

Murder is generally defined as having four elements, or components which the trier-of-fact (eg a jury) must find in order for culpability to attach. Attempted murder is the absence of the fourth element. This is not rigorous, since again, we’d have to identify the exact jurisdiction and the question didn’t indicate one. Anyone who has:

1. Has performed or omitted some act…
2. Which is the proximate cause of death…
3. With malice aforethought…
4. And the victim dies…

Is guilty of the crime of murder. As a minor discussion of these points, the first element means that positively doing something (eg cutting a safety strap) and not doing something (eg not turning off the electricity to exposed wires) can be parts of a murder charge. For the second element, the term “proximate cause” is a legal term deeply entwined with “foreseeability” and whether a chain of causation or liability connects the act with the death. A Rube Goldberg-esque manner of death might fail the proximate cause element, unless the setup was purposely concocted precisely to kill. Likewise, proximate cause isn’t always the last element in a chain of events, since that would mean a victim would be their own killer for walking into a sniper’s bullet.

The third element, malice aforethought, refers to the mental state of the accused. That is, did they genuinely intend great harm and/or death upon the victim. Different jurisdictions vary on whether an intent-to-merely-assault that leads to death can be charged with murder, and often times that’s what second-degree murder is used for. Mental state is not a binary quantity either, as different “levels” of mental state correspond to different charges, all else the same. Malice aforethought is the worst sort, corresponding to a killer that plans a victim’s death, or acts with utter disregard for any victim’s life. Lesser levels might be charged as “reckless homicide”, “negligent homicide”, etc.

Finally, the fourth element for murder is that the victim must actually die. If the victim is immediately dead and this is verifiable using the body, this is easy to prove in court. But if the victim lingers, the legal jurisdiction might adopt a “year and a day” rule, since if the victim doesn’t die quickly, then it’s assault/battery rather than murder. Or if the victim is believed to be dead but it can’t be proven – eg victim’s body never recovered – then the defense might try to argue that the victim is simply missing but alive.

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OK, so to the question. You’ve described a scenario where someone has: 1) affirmatively pressed the kill button, 2) which is believed to result in person X’s death, 3) with full intention to kill person X, but 4) person X does not die. At even a passing glance, this is not murder since person X is alive. But does it meet the first three elements to support attempted murder? Probably not, at least without additional details.

Element #1 and #3 are present, but it’s element #2 that will be problematic. It isn’t sufficient to just tell someone that “yes, this button will absolutely kill person X”. At the very minimum, the accused needs to at least be aware of the mechanism that person X will be killed, and how that relates to the “kill button”. An implied method-of-death would suffice, such as when ordering a skilled archer to assassinate a rival. Even though the accused just says “go kill him”, the accused is aware that the archer is capable of killing using their bow-and-arrow. Whereas ordering a toddler to kill the rival would be presumed as nonsensical.

If, however, the button was already demo’d to the accused as killing some other (pretend) victim first – meaning the accused has seen the manner that the “button press” leads to death – that might establish proximate cause, even if it’s not obvious what the cause of death was. If the pretend victim clutches their chest and falls down, it’s plausible to the accused that the button’s mechanism somehow involves a pacemaker malfunction. If instead the accused is told specifically that the bombs on the victim’s car will go off, then that’s a more solid establishment of element #2, although even bombs do not reliably detonate.

But there’s even more: just because a set of circumstances arguably meets the three elements for attempted murder, it’s ultimately the trier-of-fact that will have to believe it. That is to say, it would be tough to convince a jury that the accused had “absolute” certainty that the button would kill, which also affects element #1. Unless the accused admits to that after-the-fact, that’s tough to prove. What is illegal according to the elements of a crime is not the same as what will easily convince a jury.

If it seems like this elements – or really all the elements – of murder are fact-intensive, that’s because they are. Killing is as old as humans are, and how it’s been performed and how it’s been regulated/abolished has evolved over history. Modern legal scholars have to figure out how things like stochastic terrorism/killings or life-affecting afflictions (eg HIV/AIDS) should be fitted into the system of written law, because modern law requires writing down the crimes beforehand.

Without a body or even injuries and prosecution that depends entirely on proving a state of mind, you probably won’t find a jurisdiction who would give you the time of day with it. The juice isn’t worth the squeeze.

I think the attempted murder charge would fall on whoever installed the bomb and rigged up the button or the one instructing the person that if they press the button the person will die. The button presser may get away with it with the argument they were under duress.

Morally, I’d consider it attempted murder but legally, I’d find the idea of someone being prosecuted for it rather silly

Personally I’d say so but I could also see it getting taken under conspiracy to commit murder.

Depends on your jurisdiction. In Germany, the bar for murder is one of [1]:

• an [inner] desire to kill
• killing for sexual reasons
• greed
• “other despicable motivations”

and one of:

• cruelty
• insidiousness
• using “tools dangerous for public safety”
• the motivation to conceal or enable another crime.

In my layman’s understanding, pressing the button checks the ‘insidious’ box, since it is not at all expectable by the victim.

As for the first set of conditions, it would probably be down to a court ruling if the person checked the ‘desire to kill’ box (as I understand it, they wouldn’t) or the ‘other despicable motivations’ box – is killing for no reason a despicable reason?

[1] https://www.gesetze-im-internet.de/stgb/__211.html

Yes, that’s attempted murder. The method doesn’t matter, just the intent. A lawyer would likely argue that you can’t prove intent in this case, but in your hypothetical we know the intent.