- "The Cardassians might involve themselves in other people's civil wars. But we don't".
- - Admiral Chekote (DS9: "The Circle")
A civil war is a conflict internal to a culture, society, nation, or other political community.
The humanoid life forms of the planet Cheron destroyed their cities and killed each other off in a civil war and then made life uninhabitable to humanoid life forms, on that planet, in 2268. (TOS: "Let That Be Your Last Battlefield")
Bajor was on the verge of civil war several times following the Cardassian withdrawal in 2369 but a solution was often found. (DS9: "Emissary", "Shakaar")
The Mordanites of Mordan IV began a civil war that lasted forty years, due to Commander Mark Jameson supplying weapons to Karnas' rivals in 2319. (TNG: "Too Short a Season")
In 2369 a dispute between the two factions Paqu and Navot would've led into a civil war but was solved by mediator Benjamin Sisko. (DS9: "The Storyteller")
Benjamin Sisko believed a civil war would erupt between the Federation and Starfleet if the USS Lakota destroyed the USS Defiant in 2372. (DS9: "Paradise Lost")
Notable civil wars
- Vulcan Civil War (4th century)
- American Civil War (1860s)
- Xindi Civil War (ca. 1930s to 2030s)
- Mordan Civil War (2319 to 2359)
- Klaestron Civil War (mid 24th century)
- Parada Civil War (2358 to at least 2370)
- Klingon Civil War (2367 to 2368)
- Q Civil War (2373)
- Great War / Kyrian-Vaskan Civil War (beginning in late 2374)
- Borg Civil War (2377)