A bombing at a Romulan-Federation peace conference confirms the worst: The Founders have infiltrated Earth. And the methods to protect the planet may send the Federation into jackbooted paranoia.
- Adult Fear: An elderly parent with health problems who refuses to slow down or keep up with his medications.
- Alien Lunch: Why Nog likes eating at Sisko's—it's the only place where he can get tube grubs. And old Sisko actually considers putting them on the menu, though Nog is aghast when Joseph said he would cook them.Nog: What good are tube grubs if they don't wriggle on the way down?
- Apothecary Alligator: Old Sisko has one, despite not being an apothecary. Then again, it is New Orleans.
- Big Blackout: Up to Eleven—all of Earth goes dark, apparently because of Dominion sabotage.
- The Big Easy: Still has such things as horse-drawn carriages and a Creole restaurant with non-replicated food.
- Odo suggests that the Dominion might have gained cloaking technology from the Cardassian/Romulan fleet that was destroyed in the Omarian Nebula.
- A disguised changeling displays hostility towards Odo; Sisko speculates that it's because Odo is the only changeling who has ever harmed another changeling.
- Cassandra Truth: The elder Sisko actually figures out how the Changelings could easily get around blood screenings, and is completely ignored.
- To be fair, the elder Sisko only mentioned that possibility during a rant which was cut off by him having a stroke, so Captain Sisko could easily have forgotten the idea in the rush to save his father's life.
- Continuity Nod: The Federation President says there hasn't been a state of emergency on Earth in a century, barring the Borg incident.
- Control Freak: Odo hates disorder on the station and especially in his quarters, becoming infuriated when Dax pranks by moving his belongings by centimeters. It's a changeling thing.
- Elites Are More Glamorous: Nog cannot stop talking about Red Squad, a new elite group of cadets at the Academy.
- Evil Is Petty: The changeling disguised as Leyton goes out of its way to unnecessarily insult Odo, clueing him in to what's going on.
- Face Palm: Sisko's reaction to his father's stubbornness.
- When chewing out Ben over his paranoia, the elder Sisko remarks that if he were a Changeling, he'd suck the blood out of some poor solid in order to beat the blood screenings. It's revealed in the next season that, whether it's in this exact way or another way, the Dominion had already figured out how to beat blood screenings by this point in the timeline.
- When Odo offers to check in on O'Brien's and Bashir's families, Bashir tells him not to bother. Probably because of the family secret.
- Jake assures Nog that one day he'll get to join Red Squad. Yeah, about that...
- Gentle Giant: President Jaresh-Inyo is freakin' huge (his actor, Herschel Sparber, is almost seven feet tall), but he comes across as timid and almost afraid to use the powers of his office to combat the changeling threat. The writers and producers disliked the character for this reason, feeling that Jaresh-Inyo came across as too weak to be taken seriously as a president.
- Handshake Refusal: Changeling!Leyton does this to dodge Odo's attempt to expose him. Odo manages to force the issue, but the changeling still escapes.
- Immigrant Patriotism: Discussed. Jaresh-Inyo isn't a native of Earth, but he's fearful of being the President that destroys the utopia that has been created on it. Leyton on the other hand doesn't think Jaresh-Inyo can fully understand how committed he, Sisko, and the rest of humanity are to defending their homeworld.
- Jumping Off the Slippery Slope: What Sisko's father fears the Federation's "Protective measures" will bring about.
- Just Following Orders: The redshirt's response to old Sisko getting pissed over the blood tests. Ben Sisko backs him up, as he signed the order himself.
- My God, You Are Serious: Jaresh-Inyo's reaction to Sisko advising him to declare martial law.
- Noodle Incident: After downing his beer, O'Brien almost smashes his mug before Quark stops him. Apparently, he's actually done it at least once.
- Obstructive Bureaucrat: Downplayed. President Jaresh-Inyo isn't a bad guy; he's just a peacetime president in a bad situation. He's also reasonable enough to take Sisko's and Leyton's advice, even though he's not happy about it.
- Oh, Crap!: Jaresh-Inyo damn near freaks out when Sisko's briefcase shape-shifts in front of him. It turns out to be Odo, demonstrating the current Swiss Cheese Security.
- Orphaned Punchline: Courtesy of Quark.Quark: Then the Andorian says "That's not my antenna!"
- Out-of-Character Alert:
- Properly Paranoid: Jaresh-Inyo accuses Sisko and Leyton of being paranoid regarding their increased security measures—until Odo makes the above entrance, justifying their concerns.
- Reluctant Ruler: Jaresh-Inyo never really wanted to become president, and now he really regrets it.
- Shout-Out: Coming out of their WWII Pilots holoprogram, O'Brien comments they they got "cabbage crates coming over the briny".
- Stepford Smiler: Of a sort—after his stroke, old Sisko keeps up his jovial act in the restaurant despite feeling like crap.
- Stupidest Thing I've Ever Heard: How old Sisko feels about the order to test the blood of officers' families. He's even more pissed that his son signed the order.Security Officer: All family members of Starfleet personnel are required to submit to blood screenings. No exceptions.
Joe Sisko: That is the most ridiculous thing I ever heard. (to Ben Sisko) Do you believe that?
Ben Sisko: I should. I signed the orders myself.
Joe: Now why would you go and do a stupid thing like that?
- Tempting Fate: You were just asking for this one, Mr. President.President Jaresh-Inyo: Despite what happened at Antwerp, I believe the Changeling threat to be somewhat less serious than Starfleet does.Leyton: Mr. President, I assure you the threat is real.Jaresh-Inyo: For all we know, there was only one Changeling on Earth, and he might not even be here anymore.Sisko: But if he is here, we have a problem. There's no telling how much damage one Changeling can do.Jaresh-Inyo: Forgive me for saying so, Captain, but you sound a little paranoid.Sisko: Do I?[Sisko's briefcase morphs into Odo, scaring the life out of the President]Odo: Forgive the intrusion, Mr. President, but as you can see, Starfleet has every right to be concerned.Sisko: Allow me to introduce Odo, my chief of security.Jaresh-Inyo: (calming down) A very...effective...entrance, Mr. Odo.
- Swiss Cheese Security: The whole plot revolves around how Earth is completely unprepared for either changeling infiltration or direct Dominion invasion. First Odo is able to easily get close enough to the Federation President to assassinate or impersonate him. Then, after the power outage, Sisko, Leyton, and Odo are able to beam directly into the President's office from orbit.
- To Absent Friends: Bashir and O'Brien toast their fallen holographic squadmate.
- Utopia Justifies the Means: This is Sisko and Leyton's mindset for their increased security measures. However, in this case, the utopia on Earth already exists. They're just trying to protect it.
- What the Hell, Hero?: Sisko's dad gives him a huge butt-chewing for thinking that he might be a changeling, including a Full-Name Ultimatum.Joseph Sisko: Benjamin Lafayette Sisko! What the hell has gotten into your head?
- In Ben's defense, a) he was under a lot of strain at the time, and b) his father was acting strangely—not going to see a doctor for a checkup on his heart transplant, refusing blood screenings, and not eating... all things that Changeling Infiltrators might avoid doing. These two factors combine into a rather unfortunately timed package.
- Except, of course, that a Changeling infiltrator would be able to give blood and fake eating/drinking, which Odo had already demonstrated being able to do. Leaping to conclusions from vague clues makes everyone look suspicious.