It was what is considered a coup for a journalist: to catch a candidate who seemed ignorant about what he should have known. Like catching Gerald Ford saying that Poland was not seriously in thrall to the USSR, and thereby making him look like a dummy.
That happened with the public watching and Carter right there to correct him , no journalist is to be credited.
I disagree about the coup thing.
When Frost prodded Nixon into saying that the president determines for himself what is right and wrong, he was finding out something he and the rest of us didn't know about Nixon.
This is more like the time that Candidate Bush was asked about Musharraf the Pakistani general and he did not know him . When Bush became President he was in a constant conversation with Musharraf and his previous ignorance mattered little.
That a presidential candidate does not know the name of every General and battle site for the last ten years does not strike me as surprising, new, important information. Not seeking the truth about the candidate, but pushing a viewpoint about the candidate.
Hillary seems to be living in fear of being quizzed , if she is spacing press corps interviews more than three hundred days apart while running for president ... But why would anyone be upset with her for not being ready for a game of trivial pursuit?
https://www.youtube.com/watch?v=BvUZijEuNDQ