George Brown Tindall and David E. Shi, eds., America: A Narrative History, 5th ed., Vol 1 (New York: W. W. Norton and Company, 1999), 585.
In the early 1840s, the American people were no more stirred by the quarrels of Tyler and Clay over such issues as banking, tariffs, and distribution, important as they were, than students of history would be at a later date. What stirred the blood was the mounting evidence that the “empire of freedom” was hurdling the barriers of the “Great American Desert” and the Rocky Mountains, reaching out toward the Pacific coast. In 1845, an eastern editor gave a name to this bumptious spirit of expansion. “Our manifest destiny,” he wrote, “is too overspread the continent allotted by Providence for the free development of our yearly multiply millions.” At its best this much-trumpeted notion of “Manifest Destiny” offered a moral justification for American expansion, a prescription for what an enlarged United States could and should be. At its worst it was a cluster of flimsy rationalizations for naked greed and Imperial ambition. Whatever the case, hundreds of thousands of people began streaming into the Far West during the 1840s and after. The western frontier across the Mississippi River differed radically from previous western frontiers encountered by settlers from the East. Here was a new environment as well as a new culture. The Great Plains and the Far West were already occupied by Indians and Mexicans, people who had lived in the region for centuries and had established their own distinctive customs and ways of life.