Final answer:
The classification of murder as first or second degree varies by jurisdiction and is defined by specific criteria that include the presence or absence of premeditation and deliberation. Not all non-premeditated murders are automatically second degree as there are various degrees and classifications, including manslaughter, that take into account the perpetrator's mental state and circumstances of the crime.
Step-by-step explanation:
The statement, "Any murder which is not willful, deliberate, and premeditated is of the 2nd degree," is not necessarily true as the classification of murder heavily depends on the jurisdiction's laws. However, it is generally the case that first-degree murder requires an element of premeditation and deliberation, while second-degree murder does not. For instance, a spontaneous killing that arises from a heated argument might be considered second-degree. This does not automatically classify all non-willful murders as second-degree since different degrees of murder and manslaughter exist that may consider the killer's mental state, such as voluntary and involuntary manslaughter.
Considering the reference to legal cases such as Enmund v. Florida, the classification of the crime could also depend on the involvement of the accused in the felony that led to the murder without the actual intent to kill, which may result in a different charge. Moreover, in Ford v. Wainwright, the capacity of the accused to stand trial and the imposition of the death penalty is in question, suggesting that the mental state and legal competence play significant roles in determining the degree of a crime.