which economic, political and social forces were most responsible for the new imperialism that began in the la

Began where, what does la mean?

The term imperialism was used from the third quarter of the nineteenth century to describe various forms of political control by a greater power over less powerful territories or nationalities, although analytically the phenomena which it denotes may differ greatly from each other and from the "New" imperialism.

A later usage developed in the early 20th century among Marxists, who saw "imperialism" as the economic and political dominance of "monopolistic finance capital" in the most advanced countries and its acquisition — and enforcement through the state — of control of the means (and hence the returns) of production in less developed regions.

Elements of both conceptions are present in the "New imperialism" of the late 19th and early 20th centuries. But along with the adoption of ultra-nationalist and racial supremacist ideologies, the period saw a shift to pre-emptive colonial expansion, fueled by the imposition of tariff barriers aimed at excluding economic rivals from markets.

English writers have sometimes described elements of this period as the "era of empire for empire's sake," "the great adventure," and "the scramble for Africa." During this period, European nations conquered 20% of the Earth's land area (nearly 23,000,000 km²). Africa, Asia and the Pacific Islands, the remaining world regions that had largely been uncolonized by Europeans, became the primary targets of this new phase of imperialist expansion; in the latter two regions, Japan and the United States joined the European powers in the scramble for territory