Prior to the 1890s, the United States had mostly been focused on westward territorial expansion. The “foreign peoples” most of the country interacted with were Native American tribes whose land was being seized by Euroamerican settlers. Following the closing of the frontier, as described in Fredrick Jackson Turner’s influential Frontier Thesis, expansionists looked to foreign lands that might be consolidated within a new American empire. Utilizing a combination of military threats, as in Theodore Roosevelt’s “Big Stick” show of force, quite real military intervention in places like Nicaragua, and economic strategic economic pressure in China and elsewhere, the United States acquired influence abroad and came to be regarded as a major global power and the undisputed leader in the Western Hemisphere. However, not all Americans wanted an overseas empire, and groups such as the Anti-Imperialist League took a stand against aggressive overseas expansion. Territorial acquisitions such as Puerto Rico and the Philippines would come to occupy an indistinct jurisdictional status compared to the U.S. mainland, and the degree to which either territory should exercise its political and economic autonomy has been a fraught issue for over a century.

The ramifications of these geopolitical priorities and negotiations are still being felt today. The legal status of these new territories has often come into question: were they going to eventually become states, or were they something else? To resolve this, the Supreme Court decided in the Insular Cases that territories like Puerto Rico or Guam were “unincorporated.” In unincorporated territories, the Constitution only partially applies, which means that certain rights or obligations exist for the residents while others do not. This is why the residents of Puerto Rico do not have full representation in Congress.

Meanwhile, the United States has at least 750 military bases spread over the world today. The vast reach of the U.S. military that began in the 19th century continues to be an important and controversial part of global politics today, as the United States tries to uphold commitments and maintain overseas interests.

This is why studying the origins and supporting rationale of empire is so important. Review the questions below to consider other ways that American empire affects our foreign and domestic policies today.