President Thomas Jefferson wrote to a fellow scientist in late January, 1804, that "I confess I look to the duplication of area for extending a government so free and economical as ours, as a great achievement to the mass of happiness which is to ensue." Just nine months earlier the President's representatives in Paris had bargained successfully with Napoleon's bureaucrats not only to buy the port of New Orleans, then the keystone of the continent, but also to acquire, at three cents an acre, an area extending from the Mississippi River to . . . where? No one knew until Meriwether Lewis stood at the crest of the Rocky Mountains at a place known today as Lemhi Pass, on August 12, 1805.
Expansion of the American experiment created wonderful opportunities for the nation and daunting challenges for Jefferson and his circle. In the late summer of 1804, Lewis and Clark named the three rivers they deemed the sources of the Missouri River in honor of the team at the pinnacle of contemporary American statesmanship: the President himself, Secretary of State James Madison, and of the Treasury Albert Gallatin.
Gallatin's frugality and financial acumen made possible payment to France. Moreover, he pointed out that since the Constitution did not specifically deny the President authority to make the purchase, the transaction would be legal. Ever since then, the "doctrine of implied powers" has been a key element in presidential policy around the world.
Madison faced an unhappy Spain because that government had been assured by the French that it would never alienate Louisiana – nor throw the Roman Catholic creole population of New Orleans into the prison of American protestantism. He also coped with Napoleon's on-again, off-again attitude regarding the sale. Most importantly, he had been the President's confidant and support in the long planning stages.
President Jefferson was one of those western-looking aristocrats who believed that the United States should people all America. Also, he was well aware that France, Spain, and Britain also had designs on the land, people and resources west of his own republic. When his representatives, Meriwether Lewis and William Clark, set out to trace the lineaments of the Missouri River, their objective would be the debouchure of the river already named by an American explorer-trader for the popular symbol of American empire – Columbia.
With the purchase of Louisiana, the nest of nationhood would extend from the Atlantic Ocean to the Rocky Mountains, but Liberty's Rainbow arched from sea to shining sea.