War Ship

The nations of Alicetonia and Boblivia have been at war for many years now. Our Invisible Protagonist watches as Boblivia's forces are pushed back by Alicetonia's Ladies Of War, trying to figure out how to save them both.

Of course, what's going through the minds of the fans is that the Alicetonian general and the nameless Boblivian soldier who appeared a couple episodes back would make a good couple.

People like romance. People like conflict. So naturally, people like romance in the middle of a conflict. This is what happens when that comes to the front. It doesn't have to be a war, but basically any sort of conflict between two (or more) groups. It is guaranteed that the shippers will begin favoring a pairing of two characters on opposite sides... even if those specific characters don't even say two words to each other.

Related to Foe Yay; where Foe Yay is about the implications and doesn't necessarily have to garner support from the fandom, War Shipping is about the fandom support and doesn't necessarily need to be implied. Additionally, where Foe Yay is about hate as a mask for love, War Shipping doesn't have to involve any animosity at all, and the characters can be as friendly as they want to be as long as they're ultimately on opposite sides.

Not to be confused with Ship-to-Ship Combat.

Anime and Manga

 * Arguably the main plot of Mobile Suit Gundam: The 08th MS Team was the relationship between Star-Crossed Lovers Aina and Shiro, pilots on opposing sides of the One Year War.
 * Mobile Suit Gundam: Amuro and Lalah are on opposite sides.
 * Zeta Gundam: Kamille and Four, and Katz and Sarah are on opposite sides.
 * Gundam 0080: Christina and Bernard are on opposite sides.
 * Gundam Wing: Duo and Hilde start on opposite sites.
 * Gundam Seed: Cagalli and Athrun start on opposite sides.
 * Gundam Seed Destiny: Shinn and Stella are on opposite sides.
 * Gundam 00: Lyle and Anew, though it's only revealed for about one episode. Sanji and Louise also, though both are initially civilians and together, end up on opposite sides of the conflict, leading to some tension.
 * In case you couldn't tell, this is often an integral part of the Gundam Series character arcs, usually combined with, or even as often fueling, Angst and War Is Hell.

Film

 * Joyeux Noel is a movie about the platonic form of this. You can interpret it to be not so platonic.

Literature

 * In A Song of Ice and Fire fandom, a number of shippers support a pairing between enemies Ned Stark and Cersei Lannister.
 * By Schism Rent Asunder: political pragmatism throws former enemies Cayleb and Sharleyan in bed together. It ends up being a Perfectly Arranged Marriage.
 * Revenge of the Damned: Lady Atago is brave, beautiful and a military genius. She's really Sten's perfect counterpart. Too bad she's sworn to destroy the Empire.
 * Shards of Honor starts out with the Betans and the Barrayarans on opposing sides of a conflict (technically, it's Barrayar vs. Escobar, with the Betans supporting Escobar), and Betan Expeditionary Captain Cordelia Naismith being taken prisoner by Barrayaran Captain Lord Aral Vorkosigan. Four days, a lot of terrain, and some heart-to-hearts later, they're engaged. And as subsequent books tell us, they end up a pair of Happily Married Retired Badasses.
 * Luke and Mara marry just as the Empire and the New Republic reach peace.

Theatre

 * Romeo and Juliet: Romeo and Juliet fall in love, in the midst of a family feud. It does not end well.

Video Games

 * A considerable number of Star Ocean 3 fans have formed communities dedicated to Nel and Albel. Both being optional characters, they don't even interact with each other in disc 2, and that's barely any less than disc 1.
 * Tales of the Abyss has General Jozette Cecille of Kimlasca and General Aslan Frings of Malkuth, who fall in love during a temporary truce and are later given permission from their respective kingdoms to marry after the war is ended, as a symbol of the newly-forged peace.

Western Animation

 * Total Drama provides several couples who were on opposite teams during at least one season (Tyler/Lindsay in Island, Gwen/Trent and Duncan/Courtney in Action, Duncan/Gwen in World Tour), and the popularity of Crack Pairings just increases the chance of you supporting one or more of these.
 * This is part of the reason Zutara is such a popular ship. In the first two season when Zuko and Katara were on opposite sides, it added a very Romeo and Juliet-esque feel for many shippers.