system
Given the following post, respond as if you're commenting on Reddit:
human
[Star Trek] Regarding post-apocalyptic planets

Does Starfleet have any specific policy regarding how or when to contact worlds that have undergone somekind of catastrophic war or other devastating event that knocked their technological progress back a few hundred years?

Say for example a group of scientists came across a planet that showed evidence of being warp capable sometime ago, but is currently going through a nuclear winter and doesn't have any infrastructure in place to support interstellar travel. Would Starfleet try to render aid, or would they just observe the natives and only make contact after they'd managed to rebuild?
gpt
We've seen a few, and it seems to be a matter of living memory. 

In "The Apple" we see a society that may very well have been warp capable at some point. a computer has turned everyone into a bunch of childlike primitives, but it was more advanced. The Prime directive applies, although back then captains had a lot more leeway to break it especially if you could assert there was something wrong with the system. 

In "Return to Tomorrow" we see the crew encounter a bunch of semi-corporeal aliens who had lost their access to warp tech, but could rememebr it. they were picked up and carried off right quick. 

as for post season 3 TOS when the PD became much more serious, I'd say its pretty unclear.