"Space Seed" is a very good episode from Star Trek: T.O.S. season one. I personally don't think it's one of the best episodes, but it is an above average one, and one which became very important. This was mainly thanks to Harve Bennett, brought in to save the franchise after the "Star Trek: The Motion Picture" debacle. He found in "Space Seed" a worthy opponent for Kirk and his crew, resulting in the fabulous "Wrath of Khan" (R.I.P. Mr. Bennett; he passed away the same week as Leonard Nimoy, with little notice). It also resulted in the controversial re-imagining of the tale in last year's "Star Trek: Into Darkness". More about both of those films at a later date.
In "Space Seed" Khan and his followers are products of a eugenics program designed to produce "superior" human beings. The term "eugenics" comes from a Greek word which means "well born". It's a complicated topic, because so much is encompassed in it- everything from consanguinity laws to gene therapy to sterilization- but essentially it boils down to encouraging higher rates of reproduction in those with "desirable" genetic traits, while discouraging the reproduction of those with "undesirable" traits. These two components are referred to as "positive" and "negative" eugenics. I don't intend to debate the ethics of the entire philosophy here, but will say that I have grave reservations about some parts of it, and am totally opposed to other parts. There are some things which I don't believe that humans will ever have the wisdom to deal with, and some things which are just plain unethical and evil. Those considering the merits of eugenics should be given pause by some of the creepy, creepy people who have been enthusiastic practitioners: Nazi Germany and their desire for a "master race", Communist China and their one-child policy, to name a couple of examples. Then there's the question of what constitutes an "undesirable trait", and who gets to decide that question? It's always the people with power and position, while it's generally the powerless and most vulnerable who are on the receiving end of eugenics policies. For example, among their many heinous crimes against humanity, the Nazis euthanized people with Down Syndrome... now, in our "inclusive" western societies, 90% of babies with Down Syndrome are aborted. Is there a difference? Why? And who has the right to decide a life is "undesirable"? Frankly, I believe that there are some things which should just be left in the hands of God. I recommend reading G.K. Chesterton's "Eugenics and Other Evils"... he was an early opponent of this type of thing, at a time when "progressive" thinkers were enthusiastically jumping on the eugenics bandwagon.
I've strayed somewhat from "Space Seed", as the episode doesn't actually address this issue. It focuses more on a couple of Trek staples- the evils of runaway ambition, and the corruption of absolute power. Spock comments on this when analyzing the causes of the Eugenics War, saying that the scientists failed to consider that superior ability breeds superior ambition. This is certainly true of Khan, and he would be the first to admit it- or brag about it. In the 1990's, Khan and the other genetically advanced "supermen" attempted to take over the world, stopped only by a costly war. Their belief seemed to be that, as superior beings, they were the natural rulers of the world. Khan in particular seems to have ambitions which are limited only by his horizons... and with his seizure of the Enterprise, those horizons have expanded considerably. As he says to one of his revived men, before they had a world to conquer, but now the universe. It is not just territory which Khan wishes to acquire; as he tells the Enterprise crew, he also wants to search out men "willing to be led", or as McCoy acerbically points out, willing to be conquered.
Speaking of being conquered, what the dickens is the matter with Marla McGivers? The woman is an idiot. I know that T.O.S. often didn't do well writing women characters, but she takes the cake. Khan treats her like a doormat and she appears to like it, getting all dewy-eyed and wet-lipped when he's abusing and humiliating her. She's an historian... she knows what he and his people did. Yet McGivers- a Star Fleet officer- goes along with his plans, betraying her shipmates, only belatedly realizing that the former war criminal and tyrant is still capable of war crimes and tyranny. And after all of his mistreatment and villainy, she can't wait to throw herself into his power, on a planet where there'll be no escape from him no matter what he gets up to. Sheer lunacy... reminds me of those western girls who have been heading for the Middle East to become brides for Isis fighters- evil, women-abusing madmen.
Thank goodness for Lt. Uhura, who mercifully gives us a female character we can admire. Always competent at her job, she stays at her post as the bridge is slowly deprived of air until she lapses into unconsciousness. Later, as Khan towers over her, demanding that she do his bidding, she looks the "superman" straight in the eye and refuses. Then as one of his men hauls her across the room, throws her into a chair, and slaps her across the face, she still will not comply. She straightens herself up, turns and glares at him, defiant.
The best things about "Space Seed" are the the conversations between Kirk and Spock, and the interplay between Khan and Kirk. With the former, it is obvious how much Kirk relies on his first officer/ science officer, not only for information and advice, but as a sounding board, bouncing his ideas and concerns off of him. Also, at the dinner we see them working together to get Khan to betray himself to them. Spock takes the lead, asking pointed and somewhat provoking questions, while Kirk quietly sits back listening to what Khan says- and doesn't say-and watching his reaction to being challenged. Kirk is at his best in this episode- not blustering or speechifying- but observing, evaluating, and judging Khan's motives and intentions. During the first part of the episode, Kirk and Khan circle warily around each other, each seeking chinks in the other's armour. Khan is- at first- trying to keep his militant intentions (and massive ego) in check and hidden, while he tests Kirk's strength and resolve. Kirk, for his part, is controlled and wary, sensing the kind of man Khan is, but unable to act without evidence. He seeks to obtain this proof by prodding Khan, goading him, assuming that the man's need to dominate and control will sooner or later betray him. Which it does.
Having obtained evidence of Khan's actual identity, Kirk confronts him. The gloves now off, Khan is revoltingly smug and condescending in this scene, remarking on how little man has improved in 200 years. He says that Kirk couldn't possibly understand his motivations, because Kirk is physically and mentally inferior. He implies that he and his followers will easily conquer and rule over the people of this time period, and have the right to do so, as they are superior beings. This is not just naked ambition; I think it also is a philosophy which is rooted in Khan's past as a eugenicist. The whole idea of eugenics is that the propagation of superior people is to be encouraged, while that of "inferiors" is to be discouraged. To follow through with that idea to it's perhaps inevitable conclusion, the rights of the less advanced must be subordinate to those of the more advanced.
What makes Khan such a good foil for Kirk is that they actually share many of the same characteristics. Both are charismatic leaders, men of action, and intelligent, wily adversaries. And while not taken to the same extremes as Khan, Kirk obviously has his ambitions- and a healthy ego. What separates them is morality- specifically, Khan has none. He assumes that his intellectual and physical superiority gives him the right to dominate and subjugate others. Now, on many of the planets the Enterprise visits, Kirk and his crew have superior knowledge and technology, but Kirk would never dream of using it to conquer these less advanced races. This isn't to say that Kirk doesn't have his faults or make mistakes, but even when he errs, it's generally on the side of life and liberty.
Speaking of errors, I think it probably was one for Kirk to decide to drop the charges against Khan and his minions and exile them to a remote planet. We know that Kirk, while deploring Khan as a person, admires his abilities, and thinks it would be a "waste" to have such a man spend the rest of his life in lock up. Um, maybe, but so what? If Osama bin Laden had been a great sculptor or musician, shooting him would certainly be a waste of that talent, but it still would have been the right thing to do. I suspect that Kirk is acting on the very Star Trekkian notion that, given the opportunity, most people will choose to lead "good" lives. No doubt some people would choose to do so, but I personally don't think that an immoral megalomaniac who never expresses remorse for his criminal actions is likely to change very much. Perhaps Kirk was also thought dumping them on a planet in a far corner of the galaxy was a good way to avoid the worry about how to safely keep 85 super people contained, but this,too, is a flawed notion. What would happen if, for example, some unsuspecting freighter experiencing engine trouble decided to land there to effect repairs? Or- worse- what if a Klingon or Romulan vessel stumbled upon Khan and co., and decided to arm them and unleash them on the Federation? Or what if, years later, a Federation ship arrived there, not realizing what planet it was and- oh, wait....
In the end, Khan is done in by his hubris and his disdain for those he considers beneath him. Knowing himself and his people to be physically and mentally superior, Khan underestimates Kirk and his crew. He fails to realize the power which courage of conviction can give... whether it's the crew refusing to capitulate when threatened with death, or Kirk fighting him physically despite the odds. Speaking of this fight, Khan's ego is directly responsible for his loss. He had beaten Kirk- gotten the jump on him and disarmed him. But instead of shooting him, an overconfident Khan chooses to display his contempt for Kirk by destroying the phaser. Well, we know how that turned out: Kirk, in the engine room, with the lead pipe.
The episode drives home the point about Khan's downfall being due to his hubris by comparing him to Lucifer, the angel who attempted to overthrow God and was cast out. An unrepentant Khan refers to the words from Milton's Paradise Lost: "Better to reign in Hell, than serve in Heaven." It would have been equally appropriate for them to use Shakespeare's words from "Henry VIII": "Cromwell, I charge thee: fling away ambition:/ By that sin fell the angels: how can man, then/ the image of his Maker, hope to win by it?"