Imperialism is bad for either the imperialist or the conquered.

Human history has been characterized by the physical growth of states, by powerful states expanding their borders at the cost of weaker states. Since about the 19th Century, all states in the world have been more or less defined and expansion became a zero-sum game (in the eyes of all nations of the world). In order to expand, European powers had to attack and subjugate recognized sovereigns. However, the 19th Century, largely characterized by imperialism, was not in fact the darkest era of human history. In fact, it was marked by rapid progress not only of the European industrial nations, but also their colonies. Until the Age of Imperialism, the small and undeveloped nations of Africa, Asia, and Oceania had not had very large economic communities. Poor technology and under-development had restricted their areas of trade to their immediate neighbours. Basic economic sense dictates that their more exotic commodities were of little value to their immediate neighbours, where they similarly abounded. The imperialistic conquest of states in the 19th Century marked the end of this economic dark age. The military conquest and subjugation of African, Asian, and Oceanian peoples opened up a distant and wealthy market for their exotic goods. Unfortunately, this trade was generally monopolized by government-chartered European companies, but that monopoly did not extinguish economic growth. Contrarily, the monopolist companies generally had a great incentive to invest in infrastructure to increase the production of their holdings. The results of these investments included railroads in Kenya, mines in the Cape Colony, and oil wells in the Dutch East Indies. Similarly, the conquered had the good fortune to no longer be responsible for their own defence. With the vast technological differences between Europe and the rest of the world, it would undoubtedly have taken an exorbitant investment in order to compete with wealthy Europe. However, the cost for Europeans to defend their colonies was usually so small that they did not even bother to tax their colonies for the greater part of the expence. Such an alleviation of defense spending allowed the third world economies (if one believes in supply-side economics) to grow, or (if one does not) to at least raise the standard of living. Similarly, the Europeans benefited tremendously from the forcible subjugation of peoples around the world. It first and foremost opened up a source of exotic goods for which there was a demand. Secondly, it created a hungry market for the utilitarian sorts of goods that Europeans were accustomed to producing. And finally, it allowed for the strategic placement of European troops. For example, the British colonies of Sudan and Palestine shielded the Suez Canal, a vital artery of British trade. Similarly, the capture of islands throughout the Pacific secured American trade routes with China. Though the primary benefits of imperialism were economic, it undoubtedly provided great societal and political benefits as well. The English in particular often educated the best and brightest of their colonies, to create a caste of native administrators that could be trusted to be loyal to the Empire. Similarly, imperialism wiped out cultural and social institutions that were fatal to economic and political success, such as deep misgivings about trade and commerce. Imperialism also created successful administrative structures, that could be easily replicated after the imperial powers left. I anticipate that there shall be a good deal of ethical argumentation about the morality of imperialism, but there is no doubt that when one looks at the evidence, without predisposition or emotional bias, both the conqueror and the conquered come out ahead.