10 Most Important Episodes Of Star Trek: The Original Series
4. Let That Be Your Last Battlefield (3.15)
One of the more overtly political episodes of Star Trek, Let That Be Your Last Battlefield, tackles the issue of racism. Specifically, how illogical and futile the concept itself is and that when hate is allowed to grow, it will only result in catastrophe.
When the Enterprise brings aboard two aliens, one of whom is hunting the other, the conflict between the two being a result of their skin color. One is half black and half white, the other is the same, but with the colors swapped. To the crew, this difference is meaningless, but Lokai and Bele (the aliens), it's the only thing that matters. We soon find out that their planet was torn apart by a race war, with things such as slavery and segregation being involved
Even as the crew attempts to get them to settle their differences peacefully, the two simply aren't having it, trying to destroy one another and threatening the ship in the process. It then becomes clear that all they can do is return them to their planet and let things play out as they will, as they are well past the point of changing their minds. It's then pointed out that hate may not be all they ever had, but it's "all they have left."
While some have criticized this episode's commentary for being too heavy-handed, when you consider the racial climate of America in the 1960s and the decades prior, it's a heavy-handed message that came right around the time when we as a society truly needed one.