What justification did expansionists present to support their foreign policy in the late 19th century?

Expansionists in the late 19th century justified their foreign policy by promoting the idea of Manifest Destiny, which posited that the United States was destined to expand across North America and beyond. They argued that acquiring new territories would bring economic opportunities, enhance national security, and spread American ideals of democracy and civilization. Additionally, they believed that expansion was essential for competing with European powers and asserting the U.S. as a global leader. This ideology often framed Imperialism as a moral obligation to uplift "less civilized" nations.