Final answer:
The Spanish-American War was pivotal in shifting American foreign policy from isolationism to imperialism, leading to U.S. territorial acquisitions and a more interventionist role in global affairs. The outcome posed constitutional challenges and increased U.S. influence in Cuba and other territories.
Step-by-step explanation:
The Spanish-American War marked a significant transition in American foreign policy, as the United States moved from an isolationist stance to a more active and interventionist role on the global stage. This shift was underscored by the U.S.'s acquisition of territories such as Puerto Rico, Guam, and the Philippines following the war. The American military's success in the war signaled to the world that the United States had become a formidable military power, capable of exerting its influence far beyond its borders.
The war led to constitutional questions about the applicability of the Constitution to the newly acquired territories. Unlike lands added previously, these new territories were not easily integrated as states, and it was unclear if and how constitutional rights would apply to their inhabitants. The policy of 'gunboat diplomacy' and the subsequent acquisition of territories demonstrated America's intentions to expand its imperial reach, which was a dramatic change from the previous policy.
Cuba, although it did not become an American territory, faced significant U.S. influence post-war, with the Platt Amendment giving the U.S. the right to intervene in Cuban affairs and the establishment of the Guantanamo Naval Base. The Buffalo Soldiers and other military forces were instrumental in projecting U.S. power during this era, as the country pursued its imperialistic policies.