In an alternate timeline where Vulcans had remained a violent and emotional species, the Interstellar Union was the organization formed by the coming together of Andor, Earth, Tellar, and Coridan III in 2173. By the late 23rd century, the Interstellar Union incorporated eighty planets. (ST - Myriad Universes novel: The Tears of Eridanus)
By the late 23rd century the Union included other planets and species such as Yridia, Risa, the Nausicaans, Rigellians, Orions, Caitians, and the Trill. The Union had its start in the form of the Andorian Empire which had subdued other rivals such as the Tellarites and Xindi, and manipulated minor powers such as Earth and Nausicaa. Later it became an economic body intended to offset the growing strength of the Orion Free States, and eventually transformed into a political union.
Unlike the primary universe in which Earth was the Federation political capital, in this timeline, Andor was the main political capital with the Andorian Interstellar Guard serving as the Union's main exploratory and defensive force. Andorii was the primary language of the Union, and the organization was governed by the Union Prefect.
By the late 23rd century, the Union's attention was focused on the Klingon Empire as intelligence reports stated that the Klingons had conquered Gamma Hydra and reached their maximum coreward expansion prior to the Typhon Expanse. Fears mounted that the Klingons would soon turn their attention to the Union and invade via Vulcan. As a result, the Interstellar Guard had constructed a surveillance outpost on the planet to observe the primitive Vulcans in hopes of using their telepathic abilities against the Klingons. (ST - Myriad Universes novel: The Tears of Eridanus)
|Andor||Andorian Empire||Andorians, Aenar||2173||Coalition spawned from Andorian Empire. Founding member.|
|Cait||Caitians||before 2293||One of eighty IU member planets.|
|Coridan III||People's Republic of Coridan||Coridanite||2173||Founding member.|
|Earth||United Earth||Humans||2173||Former Andorian client world, now mainstay. Founding member.|
|Edos||Edoans||before 2293||One of eighty IU member planets.|
|Nausicaa||Nausicaans||22nd century||Former Andorian client world.|
|Orion||Orion Free Traders||Orions||2243||Formerly competitors of the early Union.|
|Risa||Risian Hedony||Risans||before 2293||One of the Union's mainstays.|
|Tellar||United Planets of Tellar||Tellarites||2173||Founding member.|
|Triex||Triexians||before 2293||One of eighty IU member planets.|
|Xindus||Xindi||22nd century||Bombed into submission and near-extinction by the Andorians before the founding of the IU.|
|Yridia||Yridians||22nd century||One of the Union's mainstays.|