Final answer:
The main motive for nineteenth-century imperialism was economic expansion. European and American powers sought access to raw materials and new markets for their industrial goods, driven by mercantilist ideology and supported by technological advancements such as rail and telegraph.
Step-by-step explanation:
The main motives of nineteenth-century imperialism were varied but primarily centered on economic expansion. This era was marked by European nations vying for colonial possessions to access new markets and raw materials. By establishing colonies, imperial powers aimed to enhance their wealth by exploiting local resources and creating new markets for their manufactured goods. Imperialism was driven by various motives, including the search for new lands for settlement and the desire to spread religious beliefs and cultural norms, but economic factors were dominant. Mercantilist theory posited that colonies existed to provide raw materials and markets for the mother country, thus increasing its wealth and prestige. The quest for economic expansion was also reflected in the United States, where business interests, alongside religious and progressive reformers, saw imperialism as a way to spread democratic and Christian values internationally, which in turn would benefit American economic and strategic interests.
Businesses, motivated by the profits to be made in new markets, were a major force behind imperialism. Not only were raw materials necessary for European industries, but also new markets were sought to sell the excess goods produced by the industrial revolution. The United States' move away from isolationism towards expansion was facilitated by technologies such as railroads and telegraphs, which made international trade and influence more feasible. These technologies were seen as tools to enhance internal development, spread American influence, and facilitate trade, per Exercise 14.2.4 of the inquiries. Ultimately, these various motives reinforced each other, leading to greater intensification of imperial activity throughout the nineteenth century.