As the various forms of tyranny run out of internal wealth to plunder, they turn outward:
An American statesman, John Jay, accomplished the respectable feat of compressing the whole doctrine of conquest into a single sentence. “Nations in general,” he said, “will go to war whenever there is a prospect of getting something by it.” Any considerable economic accumulation, or any considerable body of natural resources, is an incentive to conquest. The primitive technique was that of raiding the coveted possessions, appropriating them entire, and either exterminating the possessors, or dispersing them beyond convenient reach. Very early, however, it was seen to be in general more profitable to reduce the possessors to dependence, and use them as labour-motors; and the primitive technique was accordingly modified.
-Our Enemy, the State, Albert Jay Nock, pg 12
The principle was known well before Nock:
James 4:
1 ¶ From whence come wars and fightings among you? come they not hence, even of your lusts that war in your members?
2 Ye lust, and have not: ye kill, and desire to have, and cannot obtain: ye fight and war, yet ye have not, because ye ask not.
3 Ye ask, and receive not, because ye ask amiss, that ye may consume it upon your lusts.
Freedom's History 