Posted Sunday, June 30, 2002; 8:31 a.m. EST
There are so many lessons and morals to be drawn from the expedition of Lewis and Clark that each generation tends to pick a new one according to its temperament and needs. Here is one that seems suitable for us as of July 2002: If we as Americans could s ee the future, we might never set to work creating it.

When they dipped their oars into the Missouri River and started rowing west through Indian country almost 200 years ago, the captains were looking for something they would never find — because it wasn't there. The Northwest Passage, the fabled missin g link in a continuous navigable waterway between the Atlantic and the Pacific oceans, existed only in the explorers' minds, but its image was enough to move them forward, and that was enough to alter history. Their adventure, like most great ones before and since, was born of equal parts hope and ignorance, sustained by fortune and determination, and consummated by an accomplishment that was unimaginable at the outset but, looking back, appears inevitable. Columbus, remember, was trying to reach India.

What Lewis and Clark and their party finally found — although they didn't know it at the time — was not a path between the oceans but a story whose power to challenge and absorb would bridge the more profound gap between their day and ours, betw een that age of new possibilities glimpsed and this one of unforeseen upheavals survived. By the time President Jefferson sent the captains up that muddy river and out of sight, the young nation already had a Constitution, but it lacked an epic. It had a government but no real identity. Lewis and Clark helped invent one.

It still lives, despite interstate highways, despite the Web, despite vanishing forests, despite terrorism — despite everything. Great narratives never grow obsolete. There are much better maps of the West than those that the Corps of Discovery creat ed, but there are still no better stories.

And few that are so perennially relevant, as demonstrated by the effort to prepare for the expedition's bicentennial, beginning this January. In the 11 states whose land and waterways the explorers touched, plans have been under way for several years to r e-create, commemorate and just plain profit from the first and greatest American off-road trip. From the Falls of the Ohio, where a festival will celebrate the place at which Clark climbed aboard Lewis' keelboat, all the way west to tiny Fort Clatsop, Ore ., where visitors will chat with Lewis and Clark impersonators, the roadside plaques are already being engraved, the campsites cleared and the motel rooms painted. Whether one's interest in following Lewis and Clark centers on geography, natural history, Native Americans or the simple pleasure of eating a cheeseburger on the same spot where the corps was attacked by an angry grizzly, someone somewhere is hoping to be of service with a pamphlet, an exhibit, a parade, a rental canoe or a cold lemonade.

"If the expedition was just about a grand trip across the West, as great as that would be, it wouldn't capture my attention or the attention of so many Americans," says Gary Moulton, history professor at the University of Nebraska and editor of the 13-vol ume set The Journals of the Lewis & Clark Expedition. What captivates scholars like Moulton, not to mention countless amateur history buffs, is the way the story grows and changes, adapting itself to evolving American moods.

"A hundred years ago," says Dr. Mark Spence, associate professor of history at Knox College in Galesburg, Illinois, "Lewis and Clark were viewed as symbols of industrial expansion, overseas imperial trade and so on. Fifty years ago, they were really viewed as cold warriors in the forest; they epitomized the virtues of the company man. Today they are multicultural diplomats and proto-ecologists."

Lewis and Clark saw themselves as Army officers. Their instructions from their Commander in Chief were clear, and the spirit behind them was practical, not poetic: claim the West and its wealth for the U.S. With Spain to the south and Britain to the north and everything in the middle up for grabs, the first American space race had begun. The expansion of knowledge was one objective — the mission was furnished with scientific instruments — but the expansion of power was its chief goal.

"Jefferson is a good man of the Enlightenment," says James Ronda, professor of western American history at the University of Tulsa. "Knowledge is valued to the extent that it is useful. The yardstick here is always utility. He'll measure a river by its navigability. He measures land by its fertility."

The people who lived on these lands were measured too. Would the Indians help or hinder the march of progress? That was always the first question in the captains' minds as they rounded a bend in the river and saw smoke, or glimpsed a horseman watching fro m a bluff. The noble cross-cultural moments came later. Before Clark helped a teenage Sacagawea give birth inside a wintry fort, and before she repaid him a thousand times over by arranging with her Shoshone kinsmen for the expedition's passage over the R ockies, Lewis drew his sword against the Teton Sioux as they strung their bows. The whole grand endeavor might have ended right there, in the present Pierre, S.D. Had the Indians known what was coming in the years ahead, they might have wished it had.

But they couldn't see the future either. The Indians had an illusion of their own, even more magnificently mistaken than the captains' vision of the Northwest Passage: peace everlasting with this strange new race. The corps carried shiny medallions to fos ter this dream. The coins showed President Jefferson on one side and a symbolic handclasp on the reverse.

Mutual curiosity helped too. York, Clark's black slave, was a hit with the Indians, hamming it up to break the ice. In time, relations grew friendly, even intimate. The men of the corps were soldiers, not saints, and their commanders were realistic men, n ot cartoon superheroes. Lewis carried a stockpile of medicine, including potions to treat venereal diseases. He found more than a few occasions to administer the stuff to his men.