To solve these problems one needs as much an understanding of politics as an understanding of man - and the one cannot be derived from the other.

With many sovereign states, with no system of law enforceable among them, with each state judging its grievances and ambitions according to the dictates of its own reason or desire - conflict, sometimes leading to war, is bound to occur.

The most important causes of political arrangements and acts are found in the nature and behavior of man.

Asking who won a given war, someone has said, is like asking who won the San Francisco earthquake. That in war there is no victory but only varying degrees of defeat is a proposition that has gained increasing acceptance in the twentieth century.

To build a theory of international relations on accidents of geography and history is dangerous.

The transitory interests of royal houses may be advanced in war; the real interests of all people are furthered by the peace.

Then what explains war among states? Rousseau's answer is really that war occurs because there is nothing to prevent it.