In Ursula K. Le Guin's Hainish Cycle, the interstellar entity known as "The League of All Worlds" and later as "The Ekumen" is in possession of the 'ansible'. Technology makes possible instantaneous interstellar communications, and the ability to send instantaneous unmanned ships carrying bombs to another planet is exploited as well. However, living beings can't survive such travel, and thus humans are limited to space exploration done at relativistic speeds. Correspondingly, this organization, despite on occasion waging war across interstellar distances, ends up being more loose than a true empire.