One of the many amazing aspects of Meriwether Lewis and William Clark’s journey across the continental United States is their shared command of the Corps of Discovery. On this topic, Stephen Ambrose noted that “[d]ivided command almost never works and is the bane of all military men, to whom the sanctity of the chain of command is basic and the idea of two disagreeing commanders in a critical situation is anathema.”

Adding to the uniqueness of Lewis and Clark’s shared command is the two officers’ difference in rank. On June 19, 1803, Lewis wrote Clark and invited him to join the Corps of Discovery. The invitation was not offered in a subordinate capacity. Rather, Lewis contemplated the two sharing command. Aside from noting that President Thomas Jefferson would offer Clark a captain’s commission upon acceptance, Lewis declared that “your situation if joined with me in this mission will in all respects be precisely such as my own.”

While the record of the Corps of Discovery documents the success of the joint command, Lewis and Jefferson’s offer of a captain’s commission to Clark did not pan out. There being no available captain’s positions, Secretary Dearborn could only muster a lieutenant’s commission for Clark. Nevertheless, Lewis honored his joint command promise and referred to Clark as a captain throughout the trek.

Nearly 200 years after the Corps of Discovery set of up the Missouri River, President Bill Clinton made good on Lewis’ promise of rank to Clark. On January 17, 2001, President Clinton posthumously promoted Clark to the rank of captain in the Regular Army. Along with Clark’s promotion, Sacagawea and Clark’s slave York were promoted to Honorary Sergeant.

It is undeniable that Lewis and Clarks’ exploration has left an indelible impression on American history. President Clinton’s actions in promoting Clark to captain illustrates one of the many influences still felt today.