1st, 2nd, Manslaughter

Background (aka review of Law & Order basics)

Murder is homicide with "malice": (1) purpose to cause death or (2) intent to inflict serious bodily harm or (3) extreme recklessness with regard to someone's life with such unworthy purpose that it suggests callous indifference to human life. Under the typical state statute, murder is split into degrees:

First-degree murder: intentional and premeditated, or during the course of a specifically enumerated felony (felony murder). Generally punished by 15 years to a life sentence or the death penalty.

Second-degree murder: all other murder (without premeditation). Generally punished by 5 to 15 years.

Manslaughter is homicide without malice. Types:

Voluntary Manslaughter —intentional killing without malice. Killer either acted a) in heat of passion after “adequate provocation” or b) in honest but unreasonable belief that it was necessary for self-defense.

Involuntary Manslaughter —reckless or highly negligent killing. Some states break up into reckless manslaughter, negligent homicide, and vehicular manslaughter.

Question:

First off, I'm not sure I understand the difference between 2nd degree murder and voluntary manslaughter, given that in some jurisdictions, some courts have treated action in the "heat of passion" as both the distinction between (1) 1st and 2nd degree murder AND between (1) murder and [voluntary] manslaughter. At this point, after only having had 1 day of criminal law and a smattering of Law and Order episodes, I'm having trouble distinguishing the two.

Now, more as a POLICY question...

Why do we have lower sentences for 2nd degree murder (& voluntary manslaughter, since I seem to be conflating the two concepts...) than we do for 1st degree murder?

I think you could make an argument that prison sentences, at least, should be equivalent for 1st and 2nd degree murder (though perhaps death penalty should only be available for 1st degree murders, insofar as death penalty should be available at all -- but that's a different story).

If the justification for punishment is incapacitation - that is, incapacitating the perpetrator so that he cannot harm again for the period of his imprisonment, then I would argue that it is just as important to incapacitate one who intends to kill someone as a result of provocation, or in the heat of passion as it is to incapacitate one who plans to kill someone and carries out that plan. To me, the 2nd degree murderer (...& voluntary manslaughter-er) appears to be a person who cannot control his impulses.

So why not lock him up for just as long for the person who plans and schemes to kill someone? He is just as dangerous to society for his inability to temper himself, it seems to me.

Of course, there are other theories behind punishment -- deterrence, for example. Under a deterrence theory, there would be no reason to make sentences equal for 1st and 2nd degree murders. Then again, under a pure deterrence theory, I'm not sure imprisonment really deters ANY crime that is a result of provocation / lack of control of impulses, etc.

Under a retribution theory of punishment, then, yes, I guess you would punish the schemer more than the 2nd degree murderer. Maybe. Perhaps premeditation is evidence of more 'malice,' in a way, and is more deserving of punishment. Although I don't necessarily agree with that statement.

I tend to favor the incapacitation theory (combined with a little bit of retribution, I guess) behind punishment, and under that justification, I'm not sure I understand why there are different sentences at all between 1st and 2nd degree murder.

Any thoughts? You watch more Law & Order than I do, I think.

[XY comment]: I think deterrence provides a strong justification for distinguishing between 1st and 2nd degree murder. I also think part of the difference in punishment is the acknowledgement of randomness in actual outcomes and a person's responsibility for them. To the extent that a person's actions lead deterministically to another's death, that is the worst type of crime. To the extent that a person's actions were only part of the reason (i.e. other circumstances influenced the person - provocation for example) then the person is held to be less responsible. That is where deterrence comes in because a person can only be held accountable for his/her own actions. That is also how I think one should judge the different levels of murder, although the line between the different types of murder are definitely gray.