Mental States

States grade homicide based on mens rea. Sometimes they also grade on attendant circumstances, such as the status of the victim. Police, children, or multiple victims can put a homicide into a higher grade. But we will focus on mens rea.

In a simple world, we would simply use the four MPC terms to grade, purposeful killing being the worst, negligent the least bad. We do not live in a simple world, however, and even the MPC does not grade in this simple manner. But the actual grading across many states does track that intuition very roughly. 

States vary considerably in how they grade and the labels they use. Often, they will use different labels for the same grade. Again, very roughly, the grades are usually: first degree murder, second degree murder, manslaughter, and negligent homicide. Within each grade, a prosecutor might be able to prove the crime via different theories. For example, in some states, first degree murder is a klling with premediation and deliberation, but in the same state, it can also simply be felony murder. Second degree murder can be proved with differing mental states, or even felony murder. Manslaughter has two very distinct definitions. 

These divisions will become clear as we move forward. For the most part, you'll simply need to memorize the labels and the tests. For some of the labels, there will be synonyms. I'll supply those so there won't be any confusion.