The Warrantors of the Peace were a group that existed within Vulcan culture.
They were created by the philosopher Surak during the time of the Reformation. They were originally created to be hostages in order to ensure Vulcan did not end in a destructive nuclear war. In order to accomplish this, each Warrantor of a city state carried the necessary codes in order to launch a strike against their opponent. This information was embedded in a capulse that was placed in their heart and the only way to access the codes was to have the Warrantor killed. The Warrantors themselves were chosen from those closest to the leaders of the state.
By later eras, the Vulcans emphasized the use of the Warrantors to the United Federation of Planets in order to ensure peace as well but the concept was not implement until the 2260s. The Romulans later kidnapped a number of Warrantors as part of a political move to forment chaos amongst the Federation member races. (TOS novel: Dwellers in the Crucible)