I am trying to find a short story/teaser that I read in a book by (I think) either Isaac Asimov or Arthur C. Clarke. Basically, a spaceship visits a planet to resupply or something similar. They met a tribe of primitive aliens and one of the visitors thinks to himself that earlier, they would have helped the aliens to accelerate their development but now they will not be able to do that since they are fighting a war that is tearing apart their empire and civilization. Unfortunately, that is all I can remember. Any thoughts?
Arthur C. Clarke, Encounter in the Dawn, first published in 1953. No, my memory isn't that good, but I do own ACC's The Collected Stories. All his short stories, chronologically. Some quotes from the story.
It was in the last days of the Empire.
The ship held only three occupants, ...
The swaying motion of the picture as the robot walked forward...
Village, primitive native, all as you described. The story ends with a revelation that it was Earth.
Edit: Oliphaunt's description is a perfect match. My compliments on your memory. Your user name is well-chosen. ;-)
Thoughts I certainly have, although I don't have a full answer (yet). I've read a story somewhere in the past two months that fits the description. I'm pretty sure it was in a Clarke collection. I've done a bit of looking around but haven't found it yet; I'll continue hunting for that collection and update this answer when I've found it. In the mean time, though, I'd be interested to hear if this fits with the story you're looking for.
As I remember it – but this is bound to have some inaccuracies – the story I read concerned a trio of aliens who were forced to land on (what eventually turns out to be) primitive Earth for repairs, while being on their way back to their collapsing society. They have a big, remotely controlled robot that takes care of most of their exploring, to avoid having to take risks on the unknown planet themselves.
The robot encounters a primitive human hunter. A level of trust is established and the robot provides the hunter with meat, such as (if I recall correctly) a freshly killed sabre-tooth tiger. The hunter takes this back to his village and his reputation soars.
Eventually, the alien crew member himself establishes contact with the hunter, and after a while even accompanies him into the village. Not much later, however, the repairs are complete and the ship must depart. The aliens, who would normally have nursed primitive humanity to civilisation within a relatively short time (this may have been anywhere between a couple of years or two generations), instead leave some of their high-tech tools to aid their development and increase the probability of their survival.
Edit: Indeed, as noted by Hans, this was Encounter in the Dawn. I also know now why I couldn't find it: it's not in one of my two collections of Clarke's short stories, it's contained in my edition of 2001: A Space Odyssey (after the main story) – which I recently lent that out along with six other books to a colleague who's just taking his first steps into SF. :-)
The other short story included in that book is The Sentinel. Both of these served as inspirations to 2001: A Space Odyssey, and I found it nice to read them together and note the parallels.