Final answer:
The subject of the question is U.S. engagement in imperialism during the late 19th and early 20th centuries, as the nation expanded its influence to keep up with European powers and their territorial acquisitions driven by industrial competition and the pursuit of resources.
Step-by-step explanation:
In the late 19th and early 20th centuries, during a period of industrialization and geopolitical changes, the United States observed European powers expanding their empires and engaged in a form of imperialism to avoid being left behind economically and politically. Imperialism became a central theme in global politics as nations like Germany and the United States expanded to become industrial leaders. The U.S., while not a major imperial power in the sense of territory acquisition like the European scramble for Africa, nonetheless significantly influenced the trend of imperialism through its formidable economic prowess and expansion, which spurred European nations to seek new territories to maintain their competitive edge.
As a response to the challenges posed by American industrial supremacy, European nations engaged in territorial acquisitions overseas. The quest for natural resources further drove European powers to establish colonies and ports in Asia and Africa, thereby intensifying international competition. This era also saw the emergence of economic 'neo-imperialism', characterized by the economic dominance of Latin American republics by European and U.S. investors, a precursor to the larger-scale economic imperialism that would characterize later periods.