Who is noted as the only commandant to be court-martialed and relieved of their duties?

The only commandant to be court-martialed and relieved of duty was Anthony Gale. He served as the 12th commandant of the Marine Corps from 1836 to 1848 and is particularly noted for his controversial leadership style and decisions that led to dissent within the Corps. His court-martial was a significant event in the history of the Marine Corps, as it highlighted issues of command authority and accountability.

In contrast, the other individuals listed, such as Jacob Zeilen, John A. Lejeune, and General G. C. Thomas, did not face court-martial while serving in their roles, and each played distinct and important roles in the development and history of the Marine Corps without the controversies that surrounded Gale. Their legacies are instead characterized by leadership, formation of policies, and contributions to military strategy, making Anthony Gale's situation particularly unique and notable in the context of Marine Corps history.