A common theme in Deep Space Nine is complicity in the occupation of Bajor, and the resistance to that occupation. Having covered this previously with the Cardassians and Bajoran Major Kira Nerys – most notably in the episode “Necessary Evil” (2X08) – in season 5 the episode “Things Past” (5X08) shows Constable Odo’s relationship with the occupiers and occupees.
In previous episodes, Odo has usually been recognised as just an arbitrator between the two sides, but there’s plenty of examples of Odo showing himself to have authoritarian leanings. In the Mirror Universe, shown in “Crossover” (2X23), he happily works with the Klingon/Cadassian/Bajorian alliance to enslave the humans that fill the role of prime universe Bajorans on this version of Terok Nor. It is an irony that the DS9 writers seemed to enjoy: that the being with no fixed shape values order over all else, until he learns to value justice.
“Things Past” is also an episode about how much Odo has changed over the years. He has regrets about his role in the occupation, his relationship with his people, and his relationship with Kira. But he was a police officer in an authoritarian state, and no one comes out of that looking good. An underlying theme in this episode, as in many of those episodes set during the occupation, is the validity of the law in an occupied state. It’s a theme that retains its relevance in the world today.
This episode follows fairly closely after “Trials and Tribble-ations” (5X06), both of these are time travel episodes. Fortunately, the DS9 writers are happy to use all the tools in the science fiction handbook to explore the resonance of the past in the present.
This theme was also significant in the intervening episode, “Let He Who Is Without Sin…”. Having written about it before, all I’ll mention here is that the relationship the New Essentialists have to the past that they want to restore is quite different to that held by Jadzia, who actually remembers that era through the Dax symbiont.