Imperialism, practice by which powerful nations or peoples seek to extend and maintain control or influence over weaker nations or peoples. Scholars frequently use the term more restrictively: some associate imperialism solely with the economic expansion of capitalist states; others reserve it for European expansion after 1870. Although imperialism is similar in meaning to colonialism, and the two terms are sometimes used interchangeably, they should be distinguished. Colonialism usually implies formal political control, involving territorial annexation and loss of sovereignty. Imperialism refers, more broadly, to control or influence that is exercised either formally or informally, directly or indirectly, politically or economically.


Imperialism dates from antiquity, and throughout history, it has taken many forms. In any given historical period, certain forms tend to be more prevalent than others. In the ancient world, imperialism manifested itself in a series of great empires that arose when one people, usually representing a particular civilization and religion, attempted to dominate all others by creating a unified system of control. The empire of Alexander the Great and the Roman Empire are salient examples.

Early modern European imperialism (1400-1750), by contrast, generally took the form of overseas colonial expansion. Rather than one state attempting to unify the world, in this period many competing states established political control over territories in South and South East Asia and in the New World. Imperial systems were organized according to the doctrine of mercantilism: each imperial state attempted to control the trade of its colonies, in order to monopolize the benefits of that trade.

In the mid-19th century yet another variant of imperialism appeared, the imperialism of free trade. The practice endured in this period even though mercantilism and the pace of formal empire building declined significantly. European, especially British, power and influence were extended informally, mainly through diplomatic and economic means, rather than formally, through direct colonial rule. The imperialism of free trade, however, was short-lived: by the end of the 19th century, European powers were once again practising imperialism in the form of overseas territorial annexation, expanding into Africa, Asia, and the Pacific.

Since the end of World War II, when most of the formal empires were dissolved, what might be called modern economic imperialism has come to predominate. Control is exercised informally and less overtly. The United States, for instance, exerts considerable influence over certain developing nations, as a result of its national economic power and its dominance of certain international financial organizations, such as the World Bank and the International Monetary Fund. Similarly, European powers have continued to affect significantly the politics and the economics of their former colonies, and they have consequently been accused of neocolonialism—the exercise of effective sovereignty without the formality of colonial rule.


Historically, states have been motivated to pursue imperialism for a variety of reasons, which may be classified broadly as economic, political, and ideological. Theories of imperialism break down similarly, according to which motive or motives are viewed as primary.

A The Economic Motive

Economic explanations of imperialism are the most common. Proponents of this view hold that states are motivated to dominate others by the need to expand their economies, to acquire raw materials and additional sources of labour, or to find outlets for surplus capital and markets for surplus goods. The most prominent economic theories, linking imperialism with capitalism, are derived from those of Karl Marx. Lenin, for example, explained the European expansion of the late 19th century as the inevitable outcome of the need for the European capitalist economies to export their surplus capital. Similarly, contemporary Marxists have explained the post-war expansion of the United States into the Third World in terms of economic imperatives.

B Political Motives

Alternatively, some stress the political determinants of imperialism, contending that states are motivated to expand primarily by the desire for power, prestige, security, and diplomatic advantages vis-à-vis other states. In this view, late 19th-century French imperialism was intended to restore France’s international prestige after its humiliating defeat in the Franco-Prussian War. Similarly, the expansion of the Union of Soviet Socialist Republics into Eastern Europe after 1945 can be understood in terms of security needs, specifically the need to protect the nation from another invasion across its western border.

C Ideological Motives

The third set of explanations focuses on ideological or moral motives. According to this perspective, political, cultural, or religious beliefs force states into imperialism as a “missionary activity”. Britain’s colonial empire was motivated at least in part by the idea that it was the “white man’s burden” to civilize “backward” peoples. Germany’s expansion under Hitler was based in large measure on a belief in the inherent superiority of German national culture. The desire of the United States to “protect the free world” and of the former Soviet Union to “liberate” the peoples of Eastern Europe and the developing world are also examples of imperialism driven by moral and ideological concerns.

D Reactive Imperialism

Finally, some explanations of imperialism focus not on the motives of powerful states but rather on the political circumstances in weaker states. The argument holds that powerful states may not intend to expand, but may be forced to by instability on the periphery; new imperial actions result from past imperial commitments. The British conquest of India and the Russian colonization of Central Asia in the 19th century are classic examples of reactive imperialism.


Because imperialism is so often viewed as economically motivated, discussions of its effects also tend to revolve around economic issues. Disagreement arises between those who believe that imperialism implies exploitation and is responsible for the underdevelopment and economic stagnation of the poor nations and those who argue that although the rich nations benefit from imperialism, the poor nations also benefit, at least in the long run. The truth has been difficult to ascertain for at least two reasons: (1) no consensus has been reached on the meaning of exploitation, (2) it is frequently difficult to disentangle the domestic causes of poverty from those that are possibly international. What is apparent is that the impact of imperialism is uneven: some poor nations have enjoyed greater economic benefits from contact with the rich than have others. India, Brazil, and other developing nations have even begun to compete economically with their former colonial powers. Thus, it is prudent to examine the economic impact of imperialism on a case-by-case basis.

The political and psychological effects of imperialism are equally difficult to determine. Imperialism has proven both destructive and creative: for better or worse, it has destroyed traditional institutions and ways of thinking and has replaced them with the habits and mentality of the Western world.