I would not give one inch of the Mississippi to any nation, because I see in a light very
important to our peace the exclusive right to its navigation ... the Constitution has made
no provision for our holding foreign territory, still less for incorporating foreign nations
into our Union. The Executive, in seizing the fugitive occurrence which so much
advances the good of their country, have done an act beyond the Constitution. The
Legislature, in casting behind them metaphysical subtleties, and showing themselves like
faithful servants, must ratify and pay for it, and throw themselves on their country in
doing for them unauthorised what we know they would have done for themselves had
they been in a situation to do it.
This is a very important statement in American history, showing that even a strict
constitutionalist like Jefferson was prepared to dismiss the Constitution's provisions as
metaphysical subtleties' if they stood between the United States and what would soon be called its Manifest Destiny to occupy the entire northern half of the hemisphere. After Louisiana, the rest of the United States' enormous acquisitions-or depredations, depending on the viewpoint- would follow almost as a matter of course. At all events Congress approved Jefferson’s decision on October 20, 1803 and early the following year a territorial government was set up. Eight years later Louisiana was admitted to the Union, the first of thirteen states to be carved from this immense godsend. That the Louisiana affair was not merely a fortuitous aberration in Jefferson's thinking is proved by his decision, even before the purchase was arranged, to ask Congress secretly to authorize and finance an expedition to explore overland routes to the American Pacific coast. He had nurtured this idea since boyhood and ten years before, as secretary of state, he had tried to persuade the French naturalist Andrew Michaux to explorea river called Oregon' and find the shortest and most convenient route of communication between the US & the Pacific Ocean.' He now commanded his secretary, Meriwether Lewis (1774-1809), to lead an exploratory team to sort out and map the concourse of huge rivers flowing westward on the other side of the watershed from the Mississippi-Missouri headwaters. Lewis picked his army colleague William Clark (1770-11838) to join him, and they assembled and trained a party of thirty-four soldiers and ten civilians outside St Louis in the winter of 1803, before setting off on a three-year journey. Thanks to a remarkable Shoshone Indian woman, Sacajawea (1786-1812), who acted as guide and interpreter, they crossed the continental divide safely, found the Columbia River and, on November 8, 1805, gazed on the broad Pacific. Lewis went back by the same route (with detours), Clark through the Yellowstone, and they met again at Fort Union, the junction of the Yellowstone and Missouri. They then went down the Missouri, arriving back at St Louis on September 23, 1806. Both reported back in triumph to the President: In obedience to your orders we have penetrated the Continent of north America to the Pacific
Ocean, and sufficiently explored the interior of the country to affirm with confidence that we
have discovered the most practicable route which does exist across the Continent by means of
the navigable branches of the Missouri and Columbia rivers. It was one of the most successful
and comprehensive geographical adventures ever undertaken, which brought back a mass of
economic, political, military, scientific, and cartographical information recorded in copious
journals and maps. Jefferson was delighted, as well he might be: the story of the West had begun.
Five years later, John Jacob Astor (1763-1848), a German-born adventurer who had entered
America in 1784, became a fur-trader, and formed the American Fur Company (1808) and the
Pacific Fur Company (1810), founded the first trading post, Astoria, on the Pacific itself (1811)