A republic was a form of government whose head of state was elected by the people to serve as their representative. The executive and the people were governed by an ordered constitution. In the mirror universe, Spock sought to seize control the Terran Empire and establish a "constitutionally ordered, representative republic" in its place, following his contact with Captain James T. Kirk from the primary universe. Spock eventually succeeded in creating the Terran Republic, but it was soon brought down by an invasion by the Klingon-Cardassian Alliance. (TOS novel: The Sorrows of Empire)