It's the Only Way

"Roku: Shit! The volcano is erupting! Get everyone to safety while I hold it off!

Ta Min: Um, honey? If we already know that I'll be able to get everyone in this considerably tiny village into boats, and we don't care all that much about our possessions, why do you need to put yourself in mortal danger?

Roku: WOMAN, ARE YOU CONTRADICTING HERO LOGIC?

Ta Min: *sigh*"

- Avatar: The Last Airbender Condensed Episode 47

"J'onn: It's...the only way.

Dr. Fate: Hmm. Those words are always used to justify destruction."

- Justice League Unlimited, "The Return"

A crutch commonly used to justify a foolish or ridiculous course of action. There is almost always a more sensible course of action available if the characters involved would just bother to think, but that might ruin the contrived plot and/or prevent a tragic situation. And the audience better not try to think of any alternate solutions either, because "It's the only way!"

To be fair, in many dramas, it is "the only way" in the messed-up mindset of the character saying it -- television characters are frequently less reasonable and more focused than real people.

Compare with I Did What I Had to Do, the Well-Intentioned Extremist's accessory after the fact. Compare also the correlated trope When All You Have Is a Hammer.

"Sky Captain: "Is it safe?"
 * Particularly glaring in the second and third X-Men movies. In the second, Jean Grey sacrifices herself, supposedly because it's the only way to save the team; there has been considerable debate among fans about the multiple other ways they could have survived, or ways she could have saved them that would not have involved her death.
 * Eve in Face/Off believes that taking a blood sample from the man impersonating her husband is the only way to establish his identity. She could have simply taken DNA samples from him and her daughter (hair, fingerprints...) and run a comparison. Either way, additionally demanding a sample from the man with the face of the man who killed her son would have been a good idea.
 * In the climax of Tenacious D: Pick of Destiny, Jack Black challenges the Devil to a rock-off, and for the stakes declares the Devil can take (just) his partner Kyle Gass back to Hell as a sex slave if they lose. He then melodramatically urges the understandably upset Kyle that "it's the only way!".
 * Although, when you really think about it, it actually IS the only way. What better motivation to rock really hard than threats of rape by Satan himself?
 * Also, he had the deal center on his partner being taken by Satan so that he Of course, how he expected that to work is another question entirely.
 * Parodied (kind of) in the movie Snakes on a Plane, where the villain releases hundreds of venomous snakes onto a plane containing a single person he wishes to kill. When one of his lackeys wonders if there might have been a simpler plan with a higher chance of success, the villain snaps something to the effect of, "Do you think I didn't exhaust every other option?"
 * In the quoted example from Avatar: The Last Airbender above, it may in fact be justified as Roku's holding back the magma is the only thing that gives the rest of the village enough time to evacuate.
 * Spoken by Gollum in Return of the King. However, the plan was not so much ridiculous as dangerous, Gollum was nervous to have Frodo do it, and Frodo had no idea what the plan was, because it involved Gollum feeding him to a giant spider. Still, the way Frodo intended to go was suicidal at best.
 * A porcupine, in a Dilbert comic strip about When All You Have Is a Hammer: "We must stick them with quills! It's the only way!"
 * Weirdly justified in Transmorphers: A nuclear bomb needs to be placed next to a reactor. They attempt to throw it in, which is (of course) unsuccessful. So, our hero decides to put it in himself, despite the requisite 100% chance of death. . It's no less melodramatic, though.
 * Played for laughs in A Day At the Bizarro episode of Teen Titans. Why are alien tofu invading the Earth, kidnapping cows and running substitute-meat fast food chains with the intent to blow up the planet? "It is our WAY!"
 * In the pilot episode of Star Trek: Voyager, the crew decides that the only way to prevent the Kazons from taking control of the Caretaker's Array is to remain in the Delta Quadrant (rather than taking it back home) so that they can blow it up. Apparently, none of them have ever heard of time bombs.
 * Somewhat justified in that the Kazon were already there. In the middle of the battle, it was decided to destroy the array.
 * Except that the large and impressive-looking Kazon ships have no shield technology, meaning they automatically lose against anyone with Federation transporters (which could Set Them Up The Bomb or just beam their reactor core into their command bridge or vice versa)
 * Spoofed in Sky Captain and The World of Tomorrow.

Dex: "Well, there's only one way to find out."

(Sky Captain and Polly step across the booby-trapped threshold and are relieved to be unharmed)

Dex: "I meant throw something.""

"Danni: Only one way to find out!
 * There are better methodologies of discerning the superiority of one thing over another, but that doesn't mean that Harry Hill doesn't have a personal favourite.
 * Aliens: "I say we take off and nuke the entire site from orbit. It's the only way to be sure."
 * The Event uses this trope like there's no tomorrow. Unless a character hasn't thought up "the only way" yet, in which case you can be sure they will insist "I'll find a way!!!" when pressed about the fact that they have no gameplan.
 * Tales of Monkey Island:
 * Before that, De Cava says this in Chapter 3 when he says he's weaving the husks of Manatee Throat Grubs for an artificial cochlea,.
 * Subverted in Blue Beetle when Dani Garrett is about to fly her ship into a volcano, and Jaime asks if she's sure it can survive it.

Jaime: No! No! There are other ways to "find out"! Like tests and experiments!

Danni: Oh, yeah. Sorry."