First, I don't recall having read this story before. (That surprises ne right there, btw.) It read much more like a Dominic Flandry story than a Jame Retief story. I've always wondered if there was a link (or meta-link, if you will) between Flandry and Retief, because I read most of Anderson's and Laumer's available work about them around the same time during my teens, and it felt in retrospect like a ping pong match between the two writers. If this is a well-understood relationship, excuse my ignorance, but I'd be interested in comments others might have.
(Also, bear in mind I'm a foreign service kid, so writers who talk about the foreign service resonate for me -- Keith Laumer and Cordwainer Smith, for example).
My other reaction was severe annoyance at a story device Laumer uses in that piece. It's the setting of false tension by having the narrator conceal from the reader something the narrator already knows. This is incredibly common in fiction, and I've certainly used it myself more than a few times, but it's so easy to overplay. That turns a story into a "what's going on here?" exercise. Given that such a feeling is the whole point of some stories, this can be a fine thing. But turning a story into a case "Stupid Narrator Syndrome" for the sake of tension seems pointless to me.
"Diplomat at Arms" is told in tight third, with some alternate POVs and little bit of head-hopping sloppiness. Retief's scenes (which are the bulk of the story) feature a lot of introspection, inner monolog, etc. I got annoyed at Laumer for making me follow Retief through the motions of tight third while the character very carefully never thought about the whole point of what he was doing during the scenes he was on the page. There's a scene that ends with, "Retief ascended to his room to pore over the contents of his dispatch case far into the night." Very clearly he is thinking about what he is doing at that point, during the scene break.
Every now and then I realize I've had it with a narrative technique. Some years ago, for example, I made a decision to stop writing stories where sending in a man with a gun was what drove the ending. Force as a trump card is very Hollywood, and both morally and dramatically unsatisfying to me personally. I still use that ending sometimes, when the narrative specifically calls for it, but I no longer use it as a regular piece of my toolkit. Laumer has taught me to stop using false tension, again, unless the narrative specifically calls for it.
Thoughts? Counterexamples? Am I full of it? Are there techniques you've had to red-tag in your own toolbox?