What event marked the United States' rise as an imperial power?

The Spanish-American War marked a significant turning point in the rise of the United States as an imperial power. This conflict in 1898 was fought between the United States and Spain, primarily over the issue of Cuban independence. The war resulted in a swift victory for the United States, leading to the signing of the Treaty of Paris, which saw Spain cede territories such as Puerto Rico, Guam, and the Philippines to the United States.

This victory not only demonstrated military strength but also exemplified a shift in U.S. foreign policy towards imperialism. The acquisition of these territories expanded American influence considerably, marking a departure from earlier isolationist tendencies. The war showcased the United States' burgeoning global presence and set the stage for further expansion and intervention in international affairs.

In contrast, the Boxer Rebellion was a nationalist uprising in China aimed against foreign imperialism and does not directly relate to U.S. ascension as an imperial power. The Open Door Policy was a diplomatic approach advocating for equal trade rights in China, reflecting American economic interests rather than territorial expansion. The Treaty of Paris concluded the conflict but was primarily a formal agreement recognizing the outcomes of the war, rather than an event that alone indicated imperial power. Thus, the Spanish-American War is pivotal because