Why were Lewis and Clark unable to complete their mission-?

Answer 1

Interesting way to ask the question. It can be answered several ways.

In the broader sense LEWIS and Clark did complete their mission, making it all the way from the Misissippi River to the Pacific and back again with notebooks filled with information about the land and peoples, flora and fauna they experienced along the way.

In the narrowest technical sense, they could not have completed their mission, for there is no navigable water passage all the way from the Mississippi to the Pacific.

But in the strictest intellectual sense of the question, they did not complete their mission because these copious and meticulous notes they made in their journals were not published, at least not in their lifetimes and not as they probably had intended. Hence, it took decades before their scientific achievement was recognized or adequately documented.

Meriwether Lewis, the brilliant planner of the expedition, to whom the scientific writing was largely entrusted, was probably manic-depressive. He died as a victim of either suicide or murder as he made his way back to DC to make his official report to the President. However, he was already entangled in the morass of details that needed to be written up and published, and his leadership had not found a satisfying object after the expedition. Probably his adrenalin kept him on a psychological high throughout most of the expedition and suffered a letdown when it was over.

But in a symbolic sense and in the broadest, fairest intellectual sense, not only did they complete their missions as both explorers and naturalists, but they also redefined the mission to meet the obstacles they met and embodied the very spirit of exploration. They were leaders, they were managers, they were thinkers, they were writers (especially Lewis), and they were almost ideally suited as partners. They were courageous and compassionate. They proceeded with care, but they took the risks necessary to achieve their goal. They were, in fact, American heroes.

See Stephen Ambrose's dramatic account in his book Undaunted Courage -- and some of the many materials produced all along the trail for the bicentennial of the event.

Answer 2

Lewis and Clark were looking for a water route that would take them the Mississippi River to the Pacific Ocean. Since one does not exist, they did not complete that portion of their mission.