Racial prejudice and stereotyping became a major theme of Star Trek VI, and now that Star Trek had a 24th century model of the future, those in the Federation who were prejudiced prefigured an arc of development to Picard’s time, when the Federation and the Klingons would be allies.

The script emphasized the universal possibility of hidden prejudices in a series of ironies in comparison to our time: racism against Klingons was first expressed in this movie by Admiral Cartwright, played by an African American actor, Brock Peters, probably best known for his portrayal of the innocent man defended by Gregory Peck in To Kill A Mockingbird, who was nevertheless convicted by a racist jury. As he says in a DVD interview, director Nick Meyer intended this resonance. (Peters, who later played Captain Sisko’s father in Deep Space Nine, had also appeared in the Preminger film version of Porgy and Bess, along with a young chorus dancer, Nichelle Nichols.)

Meyer wanted to reinforce this by having Uhura respond to Kirk’s dinner invitation to the Klingons with the title of another Hollywood film, this one about an interracial couple, “Guess who’s coming to dinner.” When Nichelle Nichols refused to say it, the line was given to Chekhov, producing a different irony---a Russian prejudiced against the Star Trek stand-ins for the Russians.

It is a worthy theme and it all works for the story, but it was seriously out of character for the Enterprise crew, as Roddenberry, Nichols and William Shatner insisted. They had gotten past this in the original series. Even after the Klingon violence in Star Trek III, at the end of V, Kirk had been rescued by a Klingon ship, and they were all drinking together. Even Kirk’s bitterness over the Klingon execution of his son seems a bit much, a decade after it happened, especially since Kirk had only known he had a son for a few weeks.

But there is some attempt at internal justification: Kirk’s prejudice against Klingons, as well as Spock’s prejudice in favor of a Vulcan, are linked to their aging, to becoming rigid, and to a weariness as their careers come to their end. In the headquarters scene, the Enterprise crew enters talking about retirement. At the end of his one-on-one with Spock afterwards, Kirk complains that the crew is scheduled to stand down in three months, and that they’ve done their bit “for king and country.” One could argue that this film replaces racism with ageism, but this is a legitimate theme, and it does pay off later.

There is another factor. When Kirk says “the Klingons have never been trustworthy,” he is speaking from experience which they’ve all shared. It’s a fact of Star Trek history that Klingons have done bad things to the Federation. This is a consequence of conflict, which inspires anger, fear and suspicion, which precipitates more conflict, until two sides are locked into an automated and apparently inescapable dynamic. Eventually each side demonizes the other, and the longer the enmity, the more extreme the demonic stereotypes.

So aliens become not just unknown, they become automatically hostile and dangerous. The ultimate prejudice is expressed by Captain Kirk: “they’re animals.” Indeed, animals were the first aliens, and the relationship of the humans to animals is a rich story too complex to reference here. But what Kirk means is animals as not human—without the kind of reason, ethical feelings and soul, that define humans. It's what some Europeans said about the Native Americans they encountered. That’s the essence of prejudice and racism among humans: it denies the Others their humanity.