Abstract

In the first half of the nineteenth century, the United States extended its territory westward from the original border along the Mississippi River until it possessed all the territory north of the Rio Grande and south of 49° N, all the way to the Pacific Ocean. The majority of Americans approved of this expansion, which came to be termed Manifest Destiny. Concerning those American citizens who opposed Manifest Destiny, historians have constructed models that generally describe the dissent as motivated by economic self-interest, sectional friction, partisan politics, or by a lack of the technological capacity necessary to efficiently govern distant regions. These models are very useful, but do not paint a complete picture. In some cases, opposition to territorial expansion was based on a conviction that the actions being taken violated the Constitution of the United States. For some, their dissent was rooted in a sense of morality and the belief that the United States was acting in a manner dangerous to republican ideals, and a stain on the nation’s character and reputation. This thesis will examine this form of opposition as it pertains to the Louisiana Purchase, the seizing of West Florida, the War of 1812, the annexation of Oregon and Texas, and the Mexican- American War. It will present the voices of those who denied that Americans had a constitutional or moral right to grasp land held by others, not because it wasn’t in their best interests, but because they believed it was fundamentally unjust.