We ARE Struggling Together!/Literature

Examples of in  include:

"Alas for the folly of these days! said Legolas. Here all are enemies of the one Enemy, and yet I must walk blind, while the sun is merry in the woodland under leaves of gold! Folly it may seem, said Haldir. Indeed in nothing is the power of the Dark Lord more clearly shown than in the estrangement that divides all those who still oppose him."
 * In Tolkien's The Lord of the Rings books, the elves, dwarves, and men are constantly squabbling with each other when they should be joining forces to fight the Evil Overlord. The Lothlorien's elves distrusts Gimli the dwarf, and so all the Fellowship must go blind into the path to Lorien:

"Aral Vorkosigan: I could take over the universe with this army if I could ever get all their weapons pointed in the same direction."
 * This is taken Up to Eleven in The Silmarillion, where Mandos actually states in a prophecy that the elves will fail to defeat Morgoth because they are too busy fighting each other. 500 years and several million corpses later, he is proved right.
 * The Wheel of Time series may as well be called Fighting The Wrong People. While everyone agrees that everyone needs to work together in order to win the imminent Last Battle, most factions are also of the opinion that this needs to happen by them conquering the world. For instance, the Seanchan follow mostly the same prophecy everyone follows - but their version disagrees with everyone else's, so they believe they need to subdue the Dragon Reborn in order to have a chance of winning. The Dragon Reborn controls about half the continent, which required forcibly overcoming many struggling factions, embodying this trope right there. The outcome is predictable. Others such as various Aes Sedai factions see the need to cooperate, but only so long as they control everything behind the scenes (even if it means they have to kidnap and abuse the Chosen One.)
 * It certainly doesn't help that, for a while, every major faction had a Treacherous second-in-command loyal to the Dark One.
 * In Discworld novels Lord Vetinari has secretly set up several of the organisations dedicated to his overthrow, in order to keep the real ones busy with infighting. In The Discworld Companion, Vetinari's rule is credited to realising that even revolutionary anarchists want stability so they can fight their real enemies; people with a slightly different definition of revolutionary anarchy.
 * Vetinari doesn't just deal with potential rebellion this way: it's practically his whole political philosophy. "If there are two sides to an issue, see that they quickly become two hundred."
 * Further used in Night Watch, when the People's Republic of Treacle Mine Road can't even agree on what they're fighting for beyond "Truth, Justice and Freedom" (those are free, you see). They settle on
 * But subverted in that they still manage to be an effective fighting force and outright zig-zagged because it doesn't actually make any difference if they have a decisive victory or a crushing defeat. The real changes are made far away by The Chessmaster.
 * In the Strugatsky Brothers' novel Prisoners of Power, the mind-controlling totalitarian oligarchy is opposed by what may initially seem to be an unified rebel "Underground". However, to quote the novel itself, "the Underground wasn't a political party. What's more, it wasn't even a front of political parties". Its members couldn't even agree as to whether or not the mind control has to go. Factions range from blatant fascists (who want to overthrow the government and keep the mind control towers) to "biologists" (who just want to destroy the towers, but don't mind keeping the government - so they can't even agree about that), and there are factions within factions as well. It is explicitly pointed out that many prominent Underground leaders are either agents or secret allies of the government. The protagonist ultimately doesn't even bother trying to rally them, instead striking a deal with one of the less secure government leaders for inside information, recruiting a few of the more sensible Underground members and blowing up the mind control center without consulting anybody else. It is implied in later Noonverse novels that he and his allies then had to put down rebellions by some of the other groups, even though the country was already a terrible mess by then due to mind control withdrawal and such.
 * The Thrawn Trilogy, being the earliest-written look at the New Republic after the Emperor died, shows an unfortunate amount of political jockeying. Most of this can be blamed on Borsk Fey'lya and his attempts to gain power, but he's not alone. Garm Bel Iblis, after Bail Organa's death, had actually split off and formed his own rebellion against the Empire, since he thought Mon Mothma was becoming too authoritarian. One of the many plot points in the trilogy is his realizing that a great deal of her reasoning was due to The Chains of Commanding, and they could work together again.
 * Later Star Wars Expanded Universe books have the Empire shatter into squabbling warlords who fight over the true leadership while only weakening each other. In the Jedi Academy Trilogy, the one success Admiral Daala had was in reuniting those fragments and handing them over to Pellaeon after she'd lost a lot of the newly-reformed Empire's forces. Pellaeon worked at keeping the Imperial Remnant together, then decided that it could only survive by making peace with the New Republic. Of course, parts of the Empire didn't agree...
 * In Harry Potter, years of Fantastic Racism have caused various magical creatures to be suspicious of wizards and avoid them at all costs (at the same time, wizards are equally suspicious or determined to avoid said magical creatures). Almost all of them are threatened by Voldemort, but aren't really willing to work together
 * To some extent, the Last International in The Star Fraction, which seems to be mainly an umbrella label for all the forces fighting USUN. "...the ultimate conspiracy-- nothing BUT front organizations. The fronts are real, the conspiracy isn't."
 * The forces of good in the original Dragonlance Chronicles trilogy are hampered in their opposition to the Dragonarmies because their leaders are bickering over political matters that are petty by comparison. It takes drastic action, including Tasslehoff's destruction of the MacGuffin the leaders were fighting over and a "The Reason You Suck" Speech from the leader of the gods of good to get them to smarten up and unite.
 * This trope is later inverted after the Dark Queen's defeat, as her subordinates' fear of her kept them in line. Without her uniting presence, the Highlords begin fighting among themselves for control of the Dragonarmies, and become splintered into five mutually hostile factions.
 * The situation that prevailed on Barrayar at the beginning of the Vorkosigan Saga:


 * In The Stormlight Archive while the Alethi Highprinces are not actively fighting against each other, they are much more focused on outdoing each other and getting wealth and glory then they are on actually winning the war they came to fight.
 * In For Whom the Bell Tolls, Hemingway shows us the ragtag coalition of liberals, anarchists and communists that make up the Republican side in the Spanish Civil War, and he hints at the pathological purge-mania of the Stalinists. This is a case of Truth in Television.
 * Homage to Catalonia, George Orwell's nonfiction work about the Spanish Civil War, depicts the same thing.
 * The Republican-SJC coalition in Bug Jack Barron.
 * The underground in William Rotsler's To The Land Of The Electric Angel, which comprises everyone from the Pope to free-love hedonists. They actually pull off a successful revolution under the protagonist (who gets elected Pope so he can lead the uprising, and thereafter has to answer "Is the Pope Catholic?" with "No".
 * In The Left Hand of Darkness, Estraven cites the "old proverb" (which Genly suspects he made up himself) that "Karhide is not a nation but a family quarrel." Ironically, the main villain is the one trying to do something about this.