The statement is true because Lewis and Clark were indeed tasked with exploring the Louisiana Territory, and one of their objectives was to search for a northwest passage. The northwest passage referred to a hypothetical navigable river that would provide a direct route from the east coast of the United States to the western shores of North America, potentially opening up new trade routes with Asia. This concept of finding a westward route to Asia was influenced by Christopher Columbus's initial idea of reaching the Far East by sailing westward.