KIRK: Two and a half years as Chief of Starfleet Operations may have made me a stale, but I wouldn't exactly consider myself untried. They gave her back to me, Scotty.
James T. Kirk is a loyal Starfleet officer, so he'll do whatever the big brass tell him to do. That doesn't mean he has to like it. Since leaving the U.S.S. Enterprise, Kirk has been living the boring life of an office-bound Admiral, which explains his strong need to regain command of the ship. His ship.
DECKER: May I ask? Why?
KIRK: My experience, five years out there dealing with unknowns like this. My familiarity with the Enterprise, this crew.
DECKER: Admiral, this is an almost totally new Enterprise. You don't know her a tenth as well as I do.
As you might imagine, Decker is less than enthused when a washed up Admiral steals his spotlight. It must be a pretty big honor to captain a ship as legendary as the Enterprise, after all, and the dude must have worked hard to get selected for the post. Although we're psyched that Captain Kirk is back on the team, we sort of feel bad for Decker.
DECKER: I remember when you recommended me for this command. You told me how envious you were, and how much you hoped you'd find a way to get a starship command again.
Here's a shocker: Kirk and Decker have a past relationship. Kirk even helped him land the gig in the first place. Huh. This completely changes the way we understand Kirk's behavior. He might claim that he's only taking charge because he's the best person for the job, but there's more than a little ego involved in his decision.
McCOY: Your revered Admiral Nogura invoked a little known and seldom used reserve activation clause. In simpler language, Captain, they drafted me.
Unlike Kirk, McCoy is none too eager to restart life as an interstellar explorer, much less risk his life on their most dangerous mission yet. To his credit, he changes his tune as soon as Kirk explains the gravity of the situation.
KIRK: Why was my phaser order countermanded?
DECKER: Sir, the Enterprise redesign increases phaser power by channeling it through the main engines. When they went into anti-matter imbalance, the phasers were automatically cut off.
When the Enterprise gets caught up in a time-slowing wormhole, Decker defies Kirk's orders and takes charge of the situation. Kirk is pretty ticked about this, as you might imagine, but even he is forced to admit that Decker was right. He literally saved everyone's lives. This raises questions about whether Kirk is fit for duty as Enterprise's captain, or whether he's the Starfleet equivalent of an old washed-up rock star.
McCOY: The point, Captain, is that it's you who's competing. You rammed getting this command down Starfleet's throat. You've used this emergency to get Enterprise back.
We love Bones' honesty so much. Everyone has been dancing around the issue, but he's just going to say it: Kirk is using V'Ger as an excuse to retake his ship. It could've been a space-trucking accident for all he cares—all that matters is that he's back at the helm of the U.S.S. Enterprise.
McCOY: It's an obsession—an obsession that can blind you to far more immediate and critical responsibilities. Your reaction to Decker is an example.
This exchange makes us think about Captain Kirk as Captain Ahab, which is a metaphor the Star Trek series later employs to great effect in First Contact. In many ways, the Enterprise is Kirk's Moby Dick: an all-consuming obsession that threatens his own life, as well as everyone's around him.
McCOY: Well, however it's pronounced, Mister Spock, it's the Vulcan ritual supposed to purge all remaining emotions.
KIRK: The Kolinahr is also the discipline you broke to join us.
It's worth noting that Spock is actively neglecting his duty as a good Vulcan by taking part in this mission. Not only is he abandoning the Kolinahr ritual before attaining the blissful state of pure logic, but he's now actively embracing his human side and all of its emotional messiness. For (the human emotion of) shame.
DECKER: We don't know it will do. Moving into that cloud at this time is an unwarranted gamble.
KIRK: How do you define "unwarranted?"
This is a nice encapsulation of the difference between Kirk and Decker. Kirk is your classic old school adventurer: he acts first and considers the consequences later. Decker, on the other hand, prefers to weigh and analyze each decision before taking action.
KIRK: Well, Mister Decker, it seems my bluff has been called.
DECKER: I'm afraid our hand is pretty weak, Captain.
This is a small moment, but we think it shows how Decker and Kirk manage to coexist. They don't always have to agree with each other—and in fact rarely do—but they no longer feel the need to compete all the time.