Final answer:
Manifest Destiny was a 19th-century doctrine of expansion that justified American territorial growth across North America. It caused significant demographic and political shifts, leading to widespread Americanization, the exacerbation of sectional tensions over slavery, and altered international perceptions of the U.S.
Step-by-step explanation:
What is Manifest Destiny?
Manifest Destiny was a term coined in the 1840s to describe the belief that it was the United States' inevitable fate, duty, and divine right to expand its territory across the North American continent. This ideology was used to justify the expansionist policies that led to the annexation of Texas, the acquisition of Oregon, and the Mexican-American War, which resulted in the United States gaining territories in the Southwest, including California. The effects of Manifest Destiny were profound, fundamentally altering the nation's demographics, economy, and politics. It accelerated the displacement and often violent removal of Native American tribes, the annexation of new lands inflamed the debate over slavery, and it underlined the United States as a burgeoning power in North America—with European powers taking note of its growing military strength.
Effects of Manifest Destiny
The belief in Manifest Destiny led to the significant transformation of the landscape and social fabric of North America. The acquisition of new territories prompted Americanization efforts towards Indigenous peoples and Mexican residents, aiming to spread democratic ideals and economic practices. However, this expansionism also aggravated the divides between free and slave states, eventually contributing to the tensions that sparked the American Civil War. Internationally, Manifest Destiny impacted foreign relationships, particularly with Mexico and European nations, as the U.S. emerged as a formidable force in the Western Hemisphere.