[bzz01]

Good point. One answer is that manslaughter is already a special case, as it doesn't require intent to kill anyway, only negligence.

[dragonwriter]

Crimes requiring some mental state other than specific intent are fairly common, not a special case (note that this includes murder of the depraved indifference sort.)

[bzz01]

That one sounds fairly similar to manslaughter, no?

My understanding is that logically there's that basic framework of required specific intent, then there are a few crimes that allow prosecuting for negligence, then very few crimes with strict liability.

I'm originally not from US so I'm probably still getting used that the latter two categories are quite common in US law (and that strict liability is even possible).