Toward the end of The Undiscovered Country, it is revealed that
the Humans Admiral Cartwright and Colonel West, Klingon General Chang, Romulan Ambassador Nanclus, and Vulcan Lieutenant Valeris, possibly among others
were cooperating to prevent the signing of the Khitomer accords. The latter claims she's working to protect Starfleet, but it doesn't completely make sense why she'd be closely cooperating with enemies of Starfleet to do so. All of those participants have the same goal, but the reasons behind that goal is some pretty basic distrust of each other.
So how did this conspiracy happen? Was she lying about their motives?