
expansionism: A nation’s policy of broadening its territory or economic influence. expansionism when discussing manifest destiny, others see a broader expression of belief in the country’s “mission” in the world. While many writers focus primarily on U.S. Manifest destiny was used by Democrats in the 1840s to justify the war with Mexico. The phrase “manifest destiny” suggested that expansion across the American continent was obvious, inevitable, and a divine right of the United States. The concept of manifest destiny, coined by a newspaper editor, justified American expansion across the continent.