DS9: "Sanctuary"
Timely. It's definitely a flawed ep, but that last speech from the refugee leader they're sending away...
"I think you've made a terrible mistake. All of you. Maybe we could have helped you. Maybe we could have helped each other. The Skreeans are farmers, Kira. You have a famine on your planet. Perhaps we could have made that peninsula bloom again. We'll never know, will we? Fifty years of Cardassian rule have made you all frightened and suspicious. I feel sorry for you. You were right. Bajor is not Kentanna."