The Prime Directive clearly doesn't even begin to apply in "Errand of Mercy" or "A Private Little War" - it's simply not among the issues our disciplined and trained heroes would consider relevant to the situation, and is never mentioned. Is this because our heroes bend or break regulations, or because the regulations do not involve the PD in any way?
The latter explanation sounds more likely, considering Kirk isn't a criminal or a rogue. Also, none of the other episodes featuring the Prime Directive even remotely suggest that the PD would exist in order to protect "virgin" cultures from exposure to the interstellar community. In "Errand of Mercy", the PD is a tactical guide on how to best infiltrate a pre-starflight civilization; in "The Apple" and "Return of the Archons", it is a word in favor of local right of self-determination, shouted down because the locals weren't determining themselves right. In "Omega Glory", the PD just states that Starfleet skippers shouldn't declare outright war on the locals...
Timo Saloniemi
The latter explanation sounds more likely, considering Kirk isn't a criminal or a rogue. Also, none of the other episodes featuring the Prime Directive even remotely suggest that the PD would exist in order to protect "virgin" cultures from exposure to the interstellar community. In "Errand of Mercy", the PD is a tactical guide on how to best infiltrate a pre-starflight civilization; in "The Apple" and "Return of the Archons", it is a word in favor of local right of self-determination, shouted down because the locals weren't determining themselves right. In "Omega Glory", the PD just states that Starfleet skippers shouldn't declare outright war on the locals...
Timo Saloniemi