Which statement best captures the primary justification for U.S. expansion under manifest destiny?

• A. Economic opportunities compelled expansion
• B. National security concerns drove expansion
• C. Religious freedom was the primary motive
• D. It was the duty of the United States to spread democracy.

Answer: (D)

Manifest destiny centers on the belief that the United States had a destined mission to expand its political system and values across the continent, especially democracy and republican government. This gave expansion a moral purpose: not just to gain land or riches, but to extend American-style governance and rights to new territories. While economic opportunities and security concerns shaped specific moves, the core justification tied to manifest destiny is the duty to spread democracy. That framing helped justify annexations and settlements in places like Texas and Oregon by presenting them as expanding liberty and self-government rather than merely acquiring territory.