Second-degree murder is ordinarily defined as 1) an intentional killing that is not premeditated or planned, nor committed in a reasonable "heat of passion" or 2) a killing caused by dangerous conduct and the offender's obvious lack of concern for human life. Second-degree murder may best be viewed as the middle ground between first-degree murder and voluntary manslaughter.

For example, Dan comes home to find his wife in bed with Victor. At a stoplight the next day, Dan sees Victor riding in the passenger seat of a nearby car. Dan pulls out a gun and fires three shots into the car, missing Victor but killing the driver of the car.