I picked this premise up from a book. Basically, what if throughput the 50s-70s of the Cold War, the CIA actually performed assassinations on activists or politicians that were anti US in allied countries like France.
One particular assassination scenario in the book was this. During the 60s, several French politicians are campaigning to get US nukes and military bases of French soil. In response to this, Washington sends out some "specialists" to take care of these protesting politicians.
The specialists have the anti US movement politicians assassinated by making their deaths look like they were done by French revolutionaries or OAS and perform similar operations like this in other allied countries.
What if these assassinations were leaked during the Cold War and how would this affect relations between the US and allied nations? How would the Soviets use this to their advantage? What would happen to the CIA?