Star Trek: 6 Romulans Who Would Have Hated Unification (And 6 Who Wouldn't)
3. Cmdr Sela
The poster girl of the "Say No to Unification" campaign hands down is, to date, the only blonde Romulan in the franchise.
For Sela, as audiences expected, coming together in a partnership with the Vulcans would only make the Romulan Empire look weak and submissive against the Federation and the Klingons.
Her distain for the Federation comes from the way in which her mother, the alternate Tasha Yar from Yesterday's Enterprise, rejected her Romulan father's generosity. The young Sela would even play a key role in her mother's death, crying out as Tasha tried to escape and revealing their position to the guards.
Sela was a key figure in sabotaging Spock's attempts at reunification, preferring to use them as a way to conceal an invasion of Vulcan. She was also instrumental in supplying the Duras family during the Klingon Civil War, again seeking to expand the Empire's sphere of influence.
The Romulans would need to be the dominant power in any relationship for this commander. She might not be a full blooded Romulan, but her drive is purely for the survival and expansion of the Empire.