I read this many years ago and loved it, but I have no idea who wrote it or what the title of the story was. Here’s what I remember:
The story opens with an alien approaching Earth in his spaceship. The alien is some kind of caseworker whose assignment was to ensure that humans don’t destroy ourselves. To that end, he had come to earth several years before and (disguised as a human) negotiated a comprehensive peace treaty among all of the nations of the planet. This is his follow up visit, and he is looking forward to reporting what a huge success his efforts have been to his superiors. But as he goes into orbit, he notices something is amiss. There are artificial satellites in orbit; lots and lots of radio communication; rampant pollution, indiciative of industrialization; and, worst of all, radioactivity in the atmosphere indicating the development and use of atomic weapons. He is baffled by these developments, because the only way we could have advanced so far so fast would be some kind of big war, and he knows that’s impossible because of his treaty. After a bit of clandestine observing, he discovers to his dismay that there have been a number of big wars and, even more startling, no one has ever heard of the big treaty that he negotiated.
Anybody else remember this one? Who wrote it? What was it called? How did it end? Was it really any good, or was it just me being an impressionable young reader?