SISKO [OC]: That was the moment I made the decision. It was like I had stepped through a door and locked it behind me. I was going to bring the Romulans into the war.
[Captain's office]
SISKO: It's in their own best interest to join the war, that's the key. That's the reason the Romulans will finally take action. Not to do us any favours, but to protect themselves from the Dominion.