Pufendorf: On the Duty of Man and Citizen according to Natural Law

1. Consent of subjects is required to constitute any legitimate government, but it is not always and everywhere elicited in the same way. Sometimes men are compelled by military force to consent to a conqueror's rule; sometimes Citizens acquiesce of their own accord in the appointment of their prince.

2. Acquisition of authority by military force, which is usually called conquest [occupatio], occurs when a man relying upon a just cause for going to war and having been successful by force of arms and fortune reduces a people to the point that they are compelled thenceforth to submit to his authority. The legitimate title of his power is partly drawn from the fact that if he had wished as victor to take advantage of the strict rights of war, he might simply have taken the lives of the vanquished; and thus, by allowing them to get off with a lesser misfortune, he also earns a reputation for clemency. But it is also drawn from the fact that his enemy in going to war with one whom he had previously wronged, and to whom he has refused reasonable satisfaction, has placed all his fortunes on the gaming tables of Mars; he has thus already given tacit consent to whatever condition the event of war may assign him.

3. A kingdom is acquired by the free consent of a people when an election takes place by which a people (whether in process of formation or already formed) freely designates a specific man as in their opinion capable of holding power. The decision [decretum] of the people is signified to him; he accepts; the people promise obedience; power is conferred.

4. An election in a State already formed occurring after the death of the previous king is usuaJly preceded by an Interregnum. During this time the State recedes into an imperfect form, as the Citizens are then bound together only by the first contract. But a high degree of stability is provided by the love of their common country and its name, and by the fact that for most of the Citizens their fortunes are settled there. These motives constrain good Citizens to maintain peace with each other of their own accord and to make every effort to restore perfect government as soon as possible.