Supreme Commander
From Memory Alpha, the free Star Trek reference
Supreme Commander is the title given to the commander of a government's military forces.
The Chancellor of the Klingon Empire also bore the title of Klingon Supreme Commander. When Chancellor K'mpec requested that Jean-Luc Picard mediate the contenders for his replacement as Chancellor, and Picard respectfully declined, K'mpec told him that such a refusal to the dying request of the Klingon Supreme Commander would be an insult by the Federation to all Klingons. (TNG: "Reunion")
The title was utilized in the Federation Alliance during the Dominion War. On Benjamin Sisko's recommendation, Martok was made Supreme Commander of the Ninth Fleet in 2374, following Operation Return. Martok resented the position because of all the paperwork and bureaucracy involved in commanding an entire fleet. (DS9: "You Are Cordially Invited")
Supreme Commander was also the title given to Quark by Nog when they were being interrogated by Earth US Army Air Corps Captain Wainwright in 1948. (DS9: "Little Green Men")
