In the 60's Star Trek was largely a metaphor for the Cold War, but ensuing series turned Klingons into allies just as the Cold War thawed, and replaced them with new villains. Q. The Ferengi. The Borg. The Dominion. Species 8472. The Suliban. Khan and other Augments. The Xindi. As our world changed, so did our Trek villains. What do these foes, and the ethos they represent, say about our fears and the challenges we face? What about our new Trek movies and the upcoming streaming series, and what do we hope we get from our bad guys?