The Minister of War is a bureaucratic position in the Systems Commonwealth. Its details are unknown, but it is a high ranking position. Known Ministers of War are Jack Fremont, and his successor Jane Rollins. The position is an office that is occupied by someone who was voted in by popular majority.
After encountering the Templars, Captain Hunt contacted the Ministry of War about the Knights of Genetic Purity bioweapon being developed which Rollins analysis department had confirmed that the intelligence was accurate. The Minister also revealed that Constantine Stark of the Templars had connections to at least 20 signatory worlds of the New Systems Commonwealth. ("Twilight of the Idols")