This is a short story that I read in the 1990s in a hardback anthology I checked out from a public library. I think that it was one of those volumes that collected the highlights from one year's worth of The Magazine of Fantasy and Science Fiction. (But I could be wrong -- it's been roughly 20 years.)
Here's the basic plot:
The first-person narrator is a full-time writer; I think a science fiction writer.
One day, he suddenly realizes a "Secret" which holds the solution to peaceful, rational, successful resolutions of interpersonal conflicts among human beings. Not just occasionally succeeding, but consistently! He says something to the effect that normally, if a husband wants to go a hundred miles west into the mountains for a two-week vacation, and if a wife wants to go a hundred miles east to the seashore for a two-week vacation, the best that will happen is that they "compromise" by going, say, a hundred miles north, to some spot that neither of them are really happy with. (But at least one spouse has not "lost" while the other "won.") But, he asserts, by understanding and applying "the Secret" (if that's what he called it), the problem can be resolved in a way that makes everybody involved feel like a happy winner! (He doesn't say how, exactly, this would be achieved.)
Presumably, widespread knowledge of the Secret would also put an end to warfare and other unpleasant things. But before he can do much of anything with his newfound insight into the human condition, some other guys show up at his door and ask to have a private talk with him. It turns out that our narrator is far from being the first person to have stumbled across this Secret. In fact, creative writers often make this intuitive leap. But several of the people who already understand the essence of the Secret are able to predict when and where it will be independently rediscovered. Then they close in to try to recruit (or contain) the person who has just acquired this knowledge. They have some strict rules about use of the Secret, which explains why it has never yet made it out into the news media and become common knowledge.
The narrator is not willing to join their vow of silence, so they zap him with a drug (or something) which leaves his brain conscious, but temporarily unable to exercise control over the rest of his body. He can't talk coherently, he can't write anything down, etc. But he can see and hear what is happening. When the narrator's wife comes in and looks at him in concern, the visitors say that he's just had a nervous breakdown (or something similar; I'm not sure of the buzzwords they used). The narrator tells us something along the following lines: "Like every spouse of a professional writer, my wife had long been convinced that I was already teetering on the brink of lunacy, so what they were saying merely confirmed her worst fears!"
The agents of the conspiracy bundle the narrator into a car and take off toward some sort of "private hospital" (or other excuse for a detention facility) where he gets his very own cell. I don't remember if there were any statements about intentions to do anything else with him after they had him under lock and key -- such as somehow brainwashing him, or eventually killing him and calling it natural causes, or whatever.
I think the story ends with the narrator saying, in this secret manuscript he has been writing in quiet hours when no one else was watching, that now he is going to spell out the Secret for us, and then smuggle this manuscript out of the hospital somehow. He starts a sentence with some tantalizing words . . . and that's the end of it; he was never able to finish explaining how it worked!