Many factors contributed to the West’s late-nineteenth-century rush for territory in Africa and Asia, and controversies continue to rage over interpretation of the new imperialism. Despite complexity and controversy, however, basic causes are clearly identifiable.

Economic motives played an important role in the extension of political empires, especially of the British Empire. By the 1870s France, Germany, and the United States were rapidly industrializing. For a century Great Britain had been the “workshop of the world,” the dominant modern industrial power. Now it was losing its industrial leadership, as its share of global manufacturing output dropped from 33 percent to just 14 percent between 1870 and 1914, and facing increasingly tough competition in foreign markets. In this changing environment of widening economic internationalism, the world experienced one of the worst economic depressions in history, the Long Depression (originally called the Great Depression until the 1930s Great Depression supplanted it; see “The Great Depression, 1929–1939” in Chapter 30), which lasted from 1873 to 1879. To protect home industries, America and Europe (except for Britain and the Netherlands) raised tariff barriers, abandoning the century-long practice of free trade and laissez-faire capitalism (see “Liberalism and the Middle Class” in Chapter 24). Unable to export their goods and faced with excess production, market saturation, and high unemployment, Britain, the other European powers, and the United States turned to imperial expansion, seeking African and Asian colonies to sell their products and acquire cheap raw materials. The Long Depression was arguably the single most important spark touching off the age of new imperialism.

Economic gains from the new imperialism proved limited, however, before 1914. The new colonies were too poor to buy much, and they offered few immediately profitable investments. Nonetheless, colonies became important for political and diplomatic reasons. Each leading European country considered them crucial to national security, military power, and international prestige. (See “Listening to the Past: A French Leader Defends Imperialism.”)

Colonial rivalries reflected the increasing aggressiveness of Social Darwinian theories of brutal competition among races (see “Science for the Masses” in Chapter 24). As one prominent English economist argued in 1873, the “strongest nation has always been conquering the weaker . . . and the strongest tend to be best.”9 Thus European nations, considered as racially distinct parts of the dominant white race, had to seize colonies to prove their strength and virility. Moreover, since racial struggle was nature’s inescapable law, the conquest of “inferior” peoples was just. Social Darwinism and harsh racial doctrines fostered imperialist expansion.

So, too, did the industrial world’s unprecedented technological and military superiority. Three developments were crucial. First, the rapidly firing machine gun, so lethal at Omdurman in Sudan, was an ultimate weapon in many unequal battles. Second, newly discovered quinine effectively controlled malaria attacks, which had previously decimated Europeans in the tropics whenever they left breezy coastal enclaves and dared to venture into mosquito-infested interiors. Third, the introduction of steam power (see “Steam-Powered Transportation” in Chapter 23) strengthened the Western powers in two ways. Militarily, they could swiftly transport their armies by sea or rail where they were most needed. Economically, steamships with ever-larger cargoes now made round-trip journeys to far-flung colonies much more quickly and economically. Small steamboats could travel back and forth along the coast and also carry goods up and down Africa’s great rivers, as portrayed in the classic American film The African Queen. Likewise, freight cars pulled by powerful steam engines — immune to disease, unlike animals and humans — replaced the thousands of African porters hitherto responsible for carrying raw materials from the interior to the coast. Never before — and never again after 1914 — would the technological gap between the West and the non-Western regions of the world be so great.

Domestic political and class conflicts also contributed to overseas expansion. Conservative political leaders often manipulated colonial issues in order to divert popular attention from domestic problems and to create a false sense of national unity. Imperial propagandists relentlessly stressed that colonies benefited workers as well as capitalists, and they encouraged the masses to savor foreign triumphs and imperial glory.

Finally, special-interest groups in each country were powerful agents of expansion. Shipping companies wanted lucrative subsidies. White settlers wanted more land. Missionaries and humanitarians wanted to spread religion and stop the slave trade. Military men and colonial officials foresaw rapid advancement and high-paid positions in growing empires. The actions of such groups pushed the course of empire forward.