As Starfleet enforces sweeping security reforms on Earth, Sisko investigates the threat of Changelings and the Dominion. But mounting evidence indicates the entire situation could be an inside job.
- Bavarian Fire Drill: Sisko hauls in a Red Squad cadet for a chewing out, making the cadet believe Sisko's in league with Leyton. Sisko then demands the cadet walk him through the plan to sabotage the planetary power grid to explain their "damn sloppy work".
- Boring, but Practical: This episode demonstrates why Starfleet has kept the Excelsior-class ships in service for a century. The re-fitted Lakota manages to go toe-to-toe with the Defiant, a ship designed to fight the Borg, and very nearly wins.*
- False Flag Operation: Leyton's preferred motus operandi. Leyton has Red Squad disable Earth's entire power grid, then blames it on Changeling infiltrators. He also had a subspace beacon placed on the far end of the wormhole that would repeatedly open and close it to make it look like a Dominion fleet was coming into the Apha Quadrant and faked Sisko's blood test for his meeting with the President to make it look like he was a changeling.
- Frame-Up: Leyton fakes a blood screening to make Sisko look like a Changeling infiltrator, thus getting him out of the way.
- The Ghost: Lieutenant Arriaga, Leyton's mole on DS9 and the one who was causing the wormhole to open and close at random to simulate a cloaked Dominion fleet entering the Alpha Quadrant. His discovery and arrest is what prompts Leyton to order the Lakota to attack the Defiant, but he never once appears onscreen.
- Graceful Loser: Once it's clear Leyton cannot win, he quietly takes off his rank insignia in resignation.
- Hand Wave: Sisko asks (as might the audience) where Leyton got the changeling sample used in his frame-up. Leyton responds by asking whether that detail really matters at the moment, and Sisko concedes that it doesn't.
- Historical In-Joke: The Starship Lakota commanded by an officer named Benteen? Hmmmm... Double points for the Lakota and Benteen fighting a last stand for a seriously deluded officer.
- Insignia Rip-Off Ritual: Sisko pulls off Leyton's combadge when demanding his resignation. Leyton then takes off his admiral bars when admitting defeat.
- I Shall Taunt You: A Changeling takes the form of Chief O'Brien and has a chat with Sisko."We're smarter than solids. We're better than you. And most importantly, we do not fear you the way you fear us. In the end, it's your fear that will destroy you."
- Jumping Off the Slippery Slope: Admiral Leyton's methods to "Strengthen Earth" wind up shifting into violent zealotry. He's basically trying to establish a burgeoning dictatorship. His final step is declaring he will hold and defend Earth against the rest of Starfleet.
- Let's You and Him Fight: Insane Admiral Leyton sets the Lakota against the Defiant by convincing Captain Benteen that the latter ship is full of changelings.
- Named After Somebody Famous: Cadet Riley Aldrin Shepard shares two names with astronauts Buzz Aldrin and Alan Shepard.
- Not Me This Time: Yes, Changelings have infiltrated Earth. But they're innocent in this particular instance.
- Paranoia Gambit: Changeling!O'Brien elaborates on this to Sisko. There are only four changelings ! on Earth (well, so the changeling says, anyway), but just the mere thought of infiltration has sent the planet into panic.
- Rage Against the Mentor: Sisko lets Leyton have it for plotting against Jaresh-Inyo.Leyton: I only wish I'd taught you more about the importance of loyalty.
Sisko: You want to talk to me about loyalty? After you broke your oath with the Federation, lied to the people of Earth, ordered one of our own starships to fire on another! You don't have the right.
Leyton: You don't understand me at all, do you?
Sisko: I used to think I did. I used to think that you were a man of principles, a man of honor. I see that I was mistaken.
- Reasonable Authority Figure:
- Admiral Leyton is a subversion. In "Homefront", he seemed like most reasonable Starfleet admiral ever, but this episode reveals he was actually insane all along.
- President Jaresh-Inyo is a deconstruction. He's so reasonable that not only does he listen to the heroes, he also listens to the villains. After all, it's perfectly reasonable for a president to listen to his Starfleet chief of staff, especially when that admiral has evidence proving his accuser is actually a changeling.
- Rank Up: Benteen is promoted to captain and given command of the USS Lakota.
- Red Shirt: Two off-screen on the Defiant, and several more on the Lakota.
- Revealing Cover-Up: Sisko and Odo notice a transporter log indicating that Red Squad was beamed back to the San Francisco just after the blackout, demobilized, then mobilized just three hours later. When the Academy commandant asks Sisko to erase that log entry, because it might cause problems, it's their first hint that something bigger is at work.
- Sci-Fi Writers Have No Sense of Scale: Even under ideal circumstances, the largest Starfleet ships can only transport a few tens of people per minute at most. With only the Lakota available during the power outage, it would have taken far more than a day or two to garrison every city on Earth. Either they're using a very conservative definition of "city", or only a token force was provided to each one. (Which might well be the case, since Leyton, knowing the attack was bogus, would have cared more about providing the illusion of security to sway public opinion.)
- Sheathe Your Sword: The Defiant has the Lakota on the ropes, but doesn't deliver the killing blow. This convinces Benteen to disobey her orders and turn on Leyton.
- Shout-Out: The officers that Sisko mentions in the transfer log are named for characters from Catch-22.
- Smug Snake: Cadet Shepard is a smug asshole who casually boasts about having helped compromise Earth security. Don't worry, he'll get his. Also, it's not entirely clear whether the Red Squad cadets actually knew what was really going on and if they were in on the coup, so maybe he's just being proud of his work in general.
- Suspiciously Small Army: Starfleet having only one ship in the vicinity of Earth despite a time of crisis, and despite an admiral who's followers include the head of Starfleet Academy, Leyton only has the Lakota to do his bidding despite Starfleet having thousands of ships as seen later in the Dominion War. This could be less that it's the only ship in area and more it's the only ship in the area commanded by Leyton's most trusted lieutenant.
- Swiss Cheese Security: Sisko is able to get from his holding cell all the way to Leyton's office without being stopped by security, all while supposedly being wanted as a changeling infiltrator. Especially egregious since the previous episode had shown Starfleet was beefing up security at its headquarters. Then again, as Odo points out, he and Sisko helped install the security upgrades, so they would know how to circumvent them.
- That's an Order!:
- When Nog is reluctant to provide Sisko with the names of Red Squad, Sisko points out that it wasn't a request. He wants a name, and he wants it now, and that is an order!
- Leyton reiterates his orders to Benteen to stop the Defiant by any means necessary, even if it means destroying her with quantum torpedoes. Fortunately, she's sane enough to stand down.
- This Is Gonna Suck: When Leyton "exposes" Sisko as a changeling in front of Jaresh-Inyo, Sisko's response is just to toss his PADD aside in wordless frustration.
- Villainous Breakdown: Leyton seems to start one as his plans go south, but ultimately reins it in and resigns quietly.
- We Have Reserves: Leyton claims he has enough forces to "make a fight out of it." after Benteen and the Lakota crew turn on him.
- Well-Intentioned Extremist: Sisko himself says that Leyton is enacting his coup out of genuine, but misguided, patriotism.
- We Need to Get Proof: While Jaresh-Inyo is willing to listen to Sisko's theory that Leyton is planning a coup, he can't take action without evidence. Sisko and Odo immediately start gathering that evidence, also contacting Kira for help on DS9.
- What Happened to the Mouse?: We never find out what happened to the actual changeling infiltrators on Earth who bombed the Antwerp conference.
- Whole Plot Reference: It's essentially Seven Days in May IN SPACE!
- With Due Respect: Shepard says this while countering Sisko's accusations that Red Squad did "some damn sloppy work" when they caused the power outage.
- You Have to Believe Me!: Sisko's attempt to convince Jaresh-Inyo that Leyton's plotting against him comes close to this, but Sisko remains rational enough to make Inyo willing to consider the evidence.