Final answer:
The Spanish-American War of 1898 led to the United States becoming an imperial power by acquiring Spanish colonies such as Cuba, Puerto Rico, and the Philippines. The war began due to issues of Cuban independence and U.S. strategic interests, and concluded with Spain's defeat and the U.S. emerging as a significant player in global affairs.
Step-by-step explanation:
The Spanish-American War in 1898 marked a pivotal moment where the United States emerged as an imperial power. It began primarily over the issue of Cuba's independence from Spanish rule. U.S. economic interests and strategic considerations, coupled with the dramatic sinking of the USS Maine in Havana Harbor, led to a declaration of war against Spain.
American intervention in the war enabled Spain to surrender honorably against a superior force. As a result, Spain lost its colonies, including Cuba, to the United States. Cuba gained its independence, albeit with significant strings attached through the Platt Amendment, which allowed the U.S. to interfere in Cuban affairs. The consequences of the war had a lasting impact, with Puerto Rico and the Philippines also coming under U.S. control.
The imperialist drive of the U.S. was echoed by the concept of 'manifest destiny' and the strategic imperatives suggested by Alfred Mahan's naval theories. In the Pacific Ocean, the acquisition of islands like Guam served the purpose of supporting a more effective U.S. Navy and securing American dominance.