Final answer:
The acquisition of overseas territories marked the United States' movement from isolationism towards expansionism and set the stage for its participation in World War I, cementing its status as a military and economic global power.
Step-by-step explanation:
The acquisition of territories by the United States towards the end of the 19th century signified a shift from isolationism to a more expansionist policy, often referred to as imperialism.
This strategic embrace of overseas colonies, including the Philippines, Guam, and Puerto Rico, not only signaled a vested interest in international affairs but also positioned the United States as a rising global power.
This transition away from isolationism is further exemplified through the nation's entry into World War I, where the U.S. saw its participation as a responsibility to help shape global affairs, protect its economic interests, and promote democracy.
From a military standpoint, the U.S. involvement in World War I provided a significant boost to the Allied forces, helping to tip the balance against the Central Powers. On the economic front, the war effort led to a boom in U.S. production and established the country as a critical financial powerhouse.
By the end of World War I, the United States had redefined its role on the world stage, taking a step towards interventionist policies that would continue to evolve during the interwar period and into World War II.