In Deep Space Nine, Admiral Leyton, fearing war with the Dominion (which did eventually come), attempted a coup to become dictator of the Federation. He faked Dominion aggression, moved loyalists into high positions, and convinced the Federation President to declare martial law all to covertly lay the groundwork for Starfleet to take over leadership, with himself at it's head. Leyton appears as though he believed his plan to be patriotic, that in order to save the utopia of the Federation such measures were necessary, and that he was putting the needs of the many foremost. He also appears to have been Humanocentric and bigoted, in that way that people who do not see themselves as bigots make statements about the deficiencies of another group at an equal task. He also appears to believe that he's saving these things; not destroying them in the quest to preserve them. The coup plot was foiled. What if it had succeeded? Personally, I see a Federation Civil War.