Federalism and the Death Penalty

Federalism relates to the death penalty with the question of who gets to control the death penalty, the states or the national government. The Supreme Court has left it up to the States to decide whether or not to have the death penalty at all, what crimes call for the death penalty, and who gets to sentence the criminals to death. This causes major differentiation in states as to what factors decided who is sentenced to death and who isnt. For example some states say that torturing the victim is punishable by death, in others like Florida it is if the murder is “committed in a cold, calculated, and premeditated manner without any pretense or moral or legal justification.” This causes problem when the crimes occur over state lines, who gets the final say on whether or not the crime warrants the death penalty? Of course, I don't support having the death penalty and the crimes that fall under its jurisdiction becoming standardized by the supreme court because leaving it up to the States allows for a state to choose not to use capital punishment.