[11] It is not here asserted, that _present possession_ or _conquest_ are sufficient to give a title against _long possession_ and _positive laws_: but only that they have some force, and will be able to cast the balance where the titles are otherwise equal, and will even be sufficient _sometimes_ to sanctify the weaker title. What degree of force they have is difficult to determine. I believe all moderate men will allow, that they have great force in all disputes concerning the rights of princes. [12] To prevent mistakes I must observe, that this case of succession is not the same with that of hereditary monarchies, where custom has fixed the right of succession. These depend upon the principle of long possession above explained. SECTION XI. OF THE LAWS OF NATIONS. When civil government has been established over the greatest part of mankind, and different societies have been formed contiguous to each other, there arises a new set of duties among the neighbouring states, suitable to the nature of that commerce which they carry on with each other. Political writers tell us, that in every kind of intercourse a body politic is to be considered as one person; and indeed, this assertion is so far just, that different nations, as well as private persons, require mutual assistance; at the same time that their selfishness and ambition are perpetual sources of war and discord. But though nations in this particular resemble individuals, yet as they are very different in other respects, no wonder they regulate themselves by different maxims, and give rise to a new set of rules, which we call _the laws of nations_. Under this head we may comprise the sacredness of the persons of ambassadors, the declaration of war, the abstaining from poisoned arms, with other duties of that kind, which are evidently calculated for the commerce that is peculiar to different societies. But though these rules be superadded to the laws of nature, the former do not entirely abolish the latter; and one may safely affirm, that the three fundamental rules of justice, the stability of possession, its transference by consent, and the performance of promises, are duties of princes as well as of subjects. The same interest produces the same effect in both cases. Where possession has no stability, there must be perpetual war. Where property is not transferred by consent, there can be no commerce. Where promises are not observed, there can be no leagues nor alliances. The advantages, therefore, of peace, commerce, and mutual succour, make us extend to different kingdoms the same notions of justice which take place among individuals.