Manifest Destiny the belief that justified expansion.
Manifest Destiny was the belief that the United States was destined to spread across the continent. Coined in 1845, it justified the Mexican-American War, displaced Native peoples, and reignited the slavery debate. Here is the APUSH definition and why it matters.
The one-line definition
Manifest Destiny was the nineteenth-century belief that the United States was destined, by providence and by right, to expand across the North American continent from the Atlantic to the Pacific. The journalist John O’Sullivan coined the phrase in 1845.
The Manifest Destiny APUSH definition that earns points is short: the belief that American expansion across the continent was both inevitable and justified.
What to know for the exam
The idea is simple, but its consequences are where the points are.
Why it matters in APUSH
Manifest Destiny is a causation engine for Periods 4 and 5. It links westward expansion, the annexation of Texas, the Mexican-American War, and the Oregon settlement, and it feeds directly into the sectional crisis. Because every new acquisition forced the slavery question, Manifest Destiny is a standard part of arguments about the causes of the Civil War.
Common mix-ups
Manifest Destiny is the belief, not the events. It is the justification for expansion, while the Louisiana Purchase, the Mexican Cession, and the Oregon Treaty are the acquisitions it helped justify. On an essay, name the belief and then connect it to a specific acquisition to show you understand the difference.
Frequently asked questions
Quick answers — written by humans, not a chatbot.
What is the definition of Manifest Destiny for APUSH?
The nineteenth-century belief that the United States was destined and justified to expand across the North American continent. John O’Sullivan coined the term in 1845.
How did Manifest Destiny lead to the Civil War?
Every territory gained through expansion raised the question of whether slavery could spread there. Those disputes deepened sectionalism and pushed the country toward war.
Who coined the term Manifest Destiny?
The journalist John O’Sullivan, in 1845, while arguing in favor of annexing Texas.