The exercise of authority over the same area by two States is a contradiction.
The two principles referred to are Authority and Liberty, and the names of the two schools of Socialistic thought which fully and unreservedly represent one or the other of them are, respectively, State Socialism and Anarchism.
But which is the State's essential function, aggression or defence, few seem to know or care.
Aggression is simply another name for government.
And capital punishment, however ineffective it may be and through whatever ignorance it may be resorted to, is a strictly defensive act, - at least in theory.
But this is not to say that the society which inflicts capital punishment commits murder.