What Exactly Is "Manslaughter" in the Alec Baldwin Case?

Though "involuntary manslaughter" is defined by New Mexico statute to includes death caused by lack of "due caution," New Mexico precedent limits it to situations where the defendant had "subjective knowledge 'of the danger or risk to others posed by his or her actions.'"

Alec Baldwin is expected to be charged for involuntary manslaughter for the death of cinematographer Halyna Hutchins:

Baldwin has long maintained his innocence, saying in televised interviews that gun safety wasn't his responsibility and that he did not pull the trigger.

Reports prepared by FBI analysts in Virginia, however, cast doubt on that claim, saying a replica of a vintage Pietta Colt .45, "functioned normally when tested in the laboratory."

The FBI report also noted that, in order for the revolver to fire, the trigger would have been pulled.

What's all this manslaughter business, you might ask? Let's start with the New Mexico manslaughter statute (though, as we'll see, we won't end with that):

Manslaughter is the unlawful killing of a human being without malice.

A. Voluntary manslaughter consists of manslaughter committed upon a sudden quarrel or in the heat of passion.

Whoever commits voluntary manslaughter is guilty of a third degree felony resulting in the death of a human being.

So voluntary manslaughter is (to oversimplify slightly) when you mean to kill someone, and you don't have a defense such as self-defense, but the law treats the killing as a lesser crime than murder because there was some "sufficient provocation":

"All that is required (to make of the killing manslaughter) is sufficient provocation to excite in the mind of the defendant such emotions as either anger, rage, sudden resentment, or terror as may be sufficient to obscure the reason of an ordinary man, and to prevent deliberation and premeditation, and to exclude malice, and to render the defendant incapable of cool reflection."

This might include, among other things, killing someone who had just attacked you but in circumstances that don't amount to self-defense (e.g., if the attack is over and the person is leaving), or killing someone who you just learned had earlier raped a family member.

B. Involuntary manslaughter consists of manslaughter committed in the commission of an unlawful act not amounting to felony, or in the commission of a lawful act which might produce death in an unlawful manner or without due caution and circumspection.

Whoever commits involuntary manslaughter is guilty of a fourth degree felony.

Involuntary manslaughter is thus very different from the voluntary; the similarities are just that it's a homicide but not murder. One branch of it ("manslaughter committed in the commission of an unlawful act not amounting to felony") is the so-called "manslaughter-misdemeanor" rule, an analog to the "felony-murder" rule. The second branch involves, basically, causing death through negligence.

But not just any old negligence, of the sort that we're familiar with from civil cases. Rather, it has to be "criminal negligence," which is defined in New Mexico as "willful disregard of the rights or safety of others"—what some other states might call "recklessness":

In New Mexico, "the State must show at least criminal negligence to convict a criminal defendant of involuntary manslaughter." Because involuntary manslaughter is an unintentional killing, we only attach felony liability where the actor has behaved with the requisite mens rea. This Court has made clear that the criminal negligence standard applies to all three categories of involuntary manslaughter. Criminal negligence exists where the defendant "act[s] with willful disregard of the rights or safety of others and in a manner which endanger[s] any person or property." We also require that the defendant must possess subjective knowledge "of the danger or risk to others posed by his or her actions." [Emphasis added.]

Say, then, that the prosecution can show that Baldwin pointed the gun at Hutchins and pulled the trigger, but carelessly believed (without checking this for himself) that it was unloaded.

It wouldn't be enough to show that Baldwin was careless, negligent, or lacked due caution in the ordinary sense of the word. The prosecution would have to prove, beyond a reasonable doubt, that he was subjectively aware of the danger: that he actually thought about the possibility that the gun might be loaded, and proceeded to point it and pull the trigger despite that. That's much harder than just to show carelessness, or even gross carelessness, though of course much depends on what evidence the prosecution has gathered.