If there’s anything we’ve become better at over the course of human history, it’s waging war. There was a time when we were limited to the use of bows and arrows, swords, or similar weapons. The invention of the gun made it a bit easier to kill your enemy, but now we have nuclear weapons. Such weapons of mass destruction can take out large numbers of people at a time, as well as devastate the ecology of the area.
It isn’t surprising that science fiction often shows us war in the future. As much as I hope we eventually get past our tendency for destruction, it isn’t unrealistic to assume that warfare will continue to change as we advance technologically.
In Star Wars, The Empire constructs the Death Star, which is capable of destroying an entire planet without much problem. Babylon 5 also shows that both the Vorlons and the Shadows have their own planet killers. These aren’t the only examples of such technology being used. Never mind the issue of how you’d begin to power such a device. How can we ethically justify destroying an entire planet? Would it ever be justifiable? Does it depend upon the level of threat the inhabitants of that world pose to our own people? How do we determine whether they are a big enough threat to justify resorting to such drastic means?
Babylon 5 also shows a kind of brutal planetary assault at the end of the Narn-Centauri war. The Centauri used mass drivers to accelerate asteroids to hit the Narn home world. Mass Drivers had been outlawed by every civilized planet, so this action stirred up a lot of controversy. This assault killed millions of Narns, destroyed the Narn infrastructure, and wreaked havoc on the environment. How does this compare to an action such as dropping an atomic bomb? What use of weaponry is too barbaric? Too widespread?
Warfare also includes gathering information. We frequently encounter telepaths in science fiction, who could easily be used as intelligence operatives. Would employing such a method be unethical, or could it be justified if doing so saves lives? Is there a fundamental difference between searching someone’s desk for information vs. invading their mind? They are both forms of intrusion, after all, though one seems a tad more personal than the other.
Various forms of torture could also be used to extract information from people. The use of torture is controversial as it is, but time will surely help us develop new and more effective means of extracting information from unwilling people. In your mind, can torturing someone for information be justified under certain conditions, or is it always wrong?