Your political reputation affects how likely allies are to trust you and what kind of deals they'll offer at the negotiating table. There's also some emotional response in there so factions do bear grudges. Just like the real thing.
The betrayal of trust carries a heavy taboo.
Let's say a Soviet exchange student back in the '70s would go back and tell...
Deciding whether to trust or credit a person is always an uncertain task.
Espionage for the most part involves finding a person who knows something...
Fiction reveals truth that reality obscures.