Starfleet seems to let serious Romulan transgressions go.
1) Romulans attempted to blow up DS9 (successfully in another timeline)...in Visionary
2) Romulans attempted to shut down the wormhole, see above
3) Romulan Tal Shiar tried to steal the Prometheus on SD 51462 and got into a shooting battle w/2 Defiant classes and 1 Akira, while negotiating a non-aggression pact w/the Dominion (prior to SD: 51721.3
4-175) Romulan transgressions in TNG.
I just don't get letting bullies bully when there's a chance to bloody their noses and make them stop.
1) Romulans attempted to blow up DS9 (successfully in another timeline)...in Visionary
2) Romulans attempted to shut down the wormhole, see above
3) Romulan Tal Shiar tried to steal the Prometheus on SD 51462 and got into a shooting battle w/2 Defiant classes and 1 Akira, while negotiating a non-aggression pact w/the Dominion (prior to SD: 51721.3
4-175) Romulan transgressions in TNG.
I just don't get letting bullies bully when there's a chance to bloody their noses and make them stop.