The key to making sense of all this, for me, is what motivate(d)(s) the Romulans?
- Did they want power?
- Do they hate the Federation so?
- Do they want to control so they can isolate (like the Founders) ?
- Do they simply want to rule?
- Do they want to bolster they're military position?
They fear the UFP, because it is a democratic state. They are an empire/regime, to which democracy is a threat, as it could spread to them. That's how I always took it. The Duras sisters were their pawns. The Romulans called every shot in that coup. They ordered the sisters at every step, & abandoned them when they were exposed, & that is when the coup faltered