If you're not one who has strong objections to the way the Prime Directive is interpreted and applied in modern Trek, this thread may not matter to you. But at any rate...
As far as I understand it, in the days of the original series, the PD meant non-interference in the culture of pre-warp, pre-alien contact civilizations. Basically, don't tell them what kind of government to have, don't give them new technology they haven't actually developed themselves, etc. It DID NOT MEAN non-interference with natural disasters that threatened various civilizations.(This can be proved by the TOS episode "The Paradise Syndrome" where the Enterprise is trying to prevent an asteroid impact on a pre-alien contact civilization. I think this is the right episode, anyway.)
The first change seems to have come in the TNG era, when it seemed to be policy to not interfere even in the cases of natural disasters if the civilization was pre-warp, pre-alien contact. (See "Pen Pals," "Homeward," etc.)
Then, in the Voyager era, the PD seemed to mean whatever Janeway wanted. Even though the Kazon had warp drive capability and had contact with alien races, she wouldn't share Federation technology, because that would be "interference."
"Dear Doctor" is beyond the scope of this topic, since it's in a pre-PD time period, but it takes this continuing approach to a reprehensible level.
Now, the TOS-era PD could be defended on a flexible level, as long as one did not get rigid about its enforcement. (As Kirk clearly wasn't, witness "The Apple.") More technologically advanced civilizations probably shouldn't typically be going around willy-nilly interfering with other cultures and disrupting their development, but in the case of disasters that the less technologically-advanced cultures can't deal with, the UFP could still step in to help.
But to me, there is no reasonable defense for modern Trek's screw-up of the PD. I think that there was just a misinterpretation of the original concept, and it's only spiraled downward from there. Taken to the Voyager extreme, the Federation would have to be almost isolationist to avoid "cultural interference." Was this change for dramatic purposes? For example, it created conflict between Voyager and the Kazon, where otherwise there wouldn't really be a reason not to engage in trade with them.
As far as I understand it, in the days of the original series, the PD meant non-interference in the culture of pre-warp, pre-alien contact civilizations. Basically, don't tell them what kind of government to have, don't give them new technology they haven't actually developed themselves, etc. It DID NOT MEAN non-interference with natural disasters that threatened various civilizations.(This can be proved by the TOS episode "The Paradise Syndrome" where the Enterprise is trying to prevent an asteroid impact on a pre-alien contact civilization. I think this is the right episode, anyway.)
The first change seems to have come in the TNG era, when it seemed to be policy to not interfere even in the cases of natural disasters if the civilization was pre-warp, pre-alien contact. (See "Pen Pals," "Homeward," etc.)
Then, in the Voyager era, the PD seemed to mean whatever Janeway wanted. Even though the Kazon had warp drive capability and had contact with alien races, she wouldn't share Federation technology, because that would be "interference."
"Dear Doctor" is beyond the scope of this topic, since it's in a pre-PD time period, but it takes this continuing approach to a reprehensible level.
Now, the TOS-era PD could be defended on a flexible level, as long as one did not get rigid about its enforcement. (As Kirk clearly wasn't, witness "The Apple.") More technologically advanced civilizations probably shouldn't typically be going around willy-nilly interfering with other cultures and disrupting their development, but in the case of disasters that the less technologically-advanced cultures can't deal with, the UFP could still step in to help.
But to me, there is no reasonable defense for modern Trek's screw-up of the PD. I think that there was just a misinterpretation of the original concept, and it's only spiraled downward from there. Taken to the Voyager extreme, the Federation would have to be almost isolationist to avoid "cultural interference." Was this change for dramatic purposes? For example, it created conflict between Voyager and the Kazon, where otherwise there wouldn't really be a reason not to engage in trade with them.