the story: Sela attempts to sabotage Spock's efforts to reunite Romulus with Vulcan.
similar to: "Balance of Terror" (original series), "Blood Oath" (Deep Space Nine), "Redemption" (Next Generation)
my thoughts: While lightly juxtaposing, as it should have, Spock with his spiritual descendent Data, "Unification" concludes by giving Sela the big moment she needed (in order to be justified at all) and finally defines the character of the Romulans in the franchise in a satisfactory way.
It also features "a fat Ferengi," not so much a milestone moment so much as one that's always amused me. It's Riker at his most confident!
To speak of Spock's significance is something I already discussed in the first part of the story, even though the franchise icon's role is mostly explored, and featured, in this follow-up. It's one of the most important moments of the series, concluding the emotional arc begun in "Sarek" and further contrasting Next Generation from the original series. Yet Next Generation seizes the moment in a most unexpected way, also concluding the story from "Redemption" in explaining what it is that motivates Sela, the Romulan daughter the alternate Tasha Yar from "Yesterday's Enterprise."
In so doing, not only is Spock able to give further character to Vulcan interests, but Sela explains how basic Romulan frustration at the state of galactic affairs is what motivates the whole species. Though featured in the franchise fairly regularly since their debut in "Balance of Terror," the Romulans had frequently played catch-up with Klingons for overall significance, much less psychological exploration. While "The Defector" makes it clear that politics are of utmost importance to them, "Unification" makes it perfectly clear, even chilling, making way for the antagonists of Nemesis and Star Trek, Shinzon and Nero respectively, to further expand on their existential neuroses.
Strangely, although Next Generation had long made a project of the Romulans, it quickly made far greater progress with the upstart Cardassians, who went on to have even greater exploration in Deep Space Nine. It's in "Unification" where all the work comes together.
All of this makes for essential viewing.
criteria analysis: franchise - series - character - essential (all criteria met)
Leonard Nimoy (Spock)
Denise Crosby (Sela)