Prime Directive ...
Private Little War: Gave the tribes guns.
A Piece of the Action: Left the Communicator, set up a govt, and created an expectation for a Federation "cut".
Return of the Archons, and that one w/ Vaal: Took down the govt
Just about all the ones w/ a parallel earth, whether Romans, Nazis, or whatever.
I just figure that Kirk used to write one hell of an after action report back to starbase.
EXCERPT, AAR, A PRIVATE LITTLE WAR PLANET:
A BALANCE OF POWER, JUST LIKE THE BUSH WARS IN THE 20TH CENTURY ON THE ASIAN CONTINENT.
<Apparently no one told Kirk that we *lost* Vietnam>
As far as the Enterprise Incident: The plot device (Kirk is crazy!) is what was intended to protect the crew from prosecution later. Could Kirk be prosecuted by the Romulans later? Sure! Better not schedule any vacation there. He probably got a medal from his own govt.
..and I doubt that the Klingons even understand the *concept* of preserving the environment, so I dont think that eco terrorism is a worry.