Coalition of Planets
The Coalition was proposed by Nathan Samuels, the Prime Minister of United Earth in late 2154.
It was designed as an effort to build upon the work of Starfleet Captain Jonathan Archer of Enterprise NX-01, in organizing a joint military operation amongst these powers to thwart a Romulan plot to ignite interstellar war between those worlds (“Demons, Terra Prime, ENT”; “Balance of Terror, TOS”). NOTE: Their goal may have been to thwart the establishment of the Federation (obviously implying that they knew the future, speculation from Enterprise series).
2155
On January 19, 2155 initial talks for the formation of the Coalition took place on Earth in San Francisco and the participants included dignitaries from United Earth, Vulcan, the Andorian Empire, Rigel, Denobula, Coridan, and Tellar (“Demons, Terra Prime, ENT”).
March
In March of 2155, the Coalition Compact was finalized and signed, with Prime Minister Samuels as one of the signatories (ENT novel: The Good That Men Do). The conference was organized by United Earth; presided over by Minister Nathan Samuels, in San Francisco on Earth, and overseen by both the Space Probe Agency (UESPA) and Earth-Starfleet (“Demons, ENT”).
2156-2160
As the Romulan aggression heightened, the Coalition strengthened. Together they eventually defeated the Romulan Star Empire at the Battle of Cheron; effectively ending the war (“In a Mirror, Darkly – Part II, ENT”; “Star Trek: Generations” production art).
2161
The Coalition of Planets proved to be one of the most vital steps leading to the formation of the UFP in 2161 (”These Are the Voyages…, ENT”; ENT novel: The Good That Men Do.)





