Each state pursues its own interest's, however defined, in ways it judges best. Force is a means of achieving the external ends of states because there exists no consistent, reliable process of reconciling the conflicts of interest that inevitably arise among similar units in a condition of anarchy.
Kenneth WaltzTo 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.
Kenneth WaltzWar most often promotes the internal unity of each state involved. The state plagued by internal strife may then, instead of waiting for the accidental attack, seek the war that will bring internal peace.
Kenneth Waltz