Ian McDonald’s story illuminates the very problem of space opera at the short fiction length. Space opera is a mode of narration that needs (massive) space, whereupon short stories by their very nature don’t have it. It’s like squaring the circle.
I don’t think you can do space opera well (or at all) with these size limitations, the closest you end up with is a story that is a highly compressed info-dump, which Verthandi’s Ring constitutes. As a story, it reads pretty cold and detached. The main characters and their interactions are sparsely sketched and their involvement in the overall plot is one of a few decisive choices with almost not enough space to bring them to live. Given the size length, McDonaln does the best he could, buts its hardly engaging on that level, though at least it makes it understandable to some degree.
The one I would quibble with here is how McDonald presented the whole situation and the solution to the conflict. The depiction of interstellar conflict as something inevitable, something that would have happened anyway, whoever shot the first shot, is pretty debatable, even in the context of the story.
To depict life as a struggle in tooth and claw, something beyond morality, an absolute that never changes, isn’t just morally questionable, it’s not even supported by facts. For all the horrors we have on our world, all the wars still going on, we still manage a level of diplomacy on an overall level that has avoided going fully grimdark everywhere.
There are no extinctions campaigns in nature, and there’s no universal imperative for them among intelligent beings. If they actually arise, they aren’t inevitable, but the consequence of stupidity, arrogance and plain insane believes. If a writer sizes this type of argument, I always see it as a cheap short cut to not properly develop the backstory, which in this case brings us back to size. If you have to write space opera at short stories lengths, you have to compress, both the content and the setting. Saying that war between interstellar cultures is a given, is just such a compression artifact.
This might read like I didn’t like the story, but you would be wrong. Despite my qualms with the underpinnings of the story and with solving a problem by dumping genocidal aliens on another universe, I like the scale on which the story operates and the future culture depicted. But it feels too much like there’s a longer novel trying to crawl out of this story, one that could have been much better given the right amount of space to grow and mature.