We Have Become Complacent

""Five years ago, I lost thirty thousand men in the blink of an eye...and the world just fucking watched. Tomorrow, there will be no shortage of volunteers, no shortage of patriots. I know you understand.""

- General Shepherd, Modern Warfare 2

Sometimes directly pointed out by a war veteran or someone with a lot of experience in life, this trope is about some society growing complacent with peace and reluctant to think anything bad can happen. Little do they know that their ancient enemies are gearing up for the war that will slaughter thousands, if not millions, of civilians For the Evulz. Sometimes done anviliciously, sometimes it's just part of the plot. Don't be surprised if the society heavily frowns upon violence, even in self-defense. Expect the heroes to try to stop the evil plan, either by alerting the populace or by fighting behind the scenes. If they fail, expect their country to be a Soiled City on a Hill or an Easily-Conquered World.

If there is an epilogue, expect an And Man Grew Proud.

Anime and Manga
"My beloved brother, Garma Zabi, was sacrificed. WHY?! The war is at a stalemate.  Perhaps many of you have become complacent!"
 * In Mobile Suit Gundam, Gihren Zabi accuses the Principality of Zeon of this in his "Sieg Zeon!" Rousing Speech:


 * Twilight of the Cockroaches. A society of cockroaches, flourishing under the passive acceptance of a depressed bachelor, is completely unprepared when he begins dating a neat freak...

Comic Books
"Caesar: "Look at yourselves! You have become decadent! All you think about nowadays is eating and sleeping!" Senator (waking up): "What? It's lunchtime already?""
 * One of Alan Moore's "Future Shocks" for 2000 AD is about a legion of soldiers sent into space by their home planet's emperor after all their enemies there have been defeated. Their mission is to travel through space in a straight line and destroy everything in their path until they reach the end of the universe. After over a billion years, the soldiers find a planet up ahead that once had the reputation of a great empire but has since become "soft and flabby." They decide to lay waste to it and later discover that it was their own home world, because the universe is curved and circular.
 * In one Asterix album, Julius Caesar scolds his senators:


 * The backstory to the Silver Surfer involves this trope: his home planet Zenn-la used to have a space programme, but the people dismantled it and went home to go Crystal Spires and Togas, meaning all of them would have been wiped out by Galactus if Norrin Radd hadn't saved them by sacrificing himself to become the Surfer.

Film

 * Pretty much the point of Richard Harris' final speech in Cromwell.

Literature
The Cry of Yamar! How long had it been since anyone had quoted that in my hearing? Why should anyone on Beltane? Yamar was a prophet of soldiers; his saga was one learned by recruits to point the difference between civilian and fighting man.
 * "So be it--" That was Lugard once more, but he sounded very tired. "'And when Yamar lifted up his voice, they did not listen. And when he cried aloud, they put their hands to their ears, laughing. And when he showed them the cloud upon the mountains, they said it was afar and would come not nigh. And when a sword glinted in the hills and he pointed to it, they said it was but the dancing of a brook in the sun.'"
 * Society in Codex Alera had become complacent due to dependence on furycrafting. The power a person possessed determined their place in that society, with the most powerful becoming the High Lords while the least powerful had no place in the citizenry. Naturally the people without strong furycraft would develop strong minds that could enhance society, but because they didn't have strong furycraft they were always ignored. The people with strong furycraft were content with where society was and had no drive to enhance it, which promoted stagnation. Tavi recognized this problem
 * It also applied to the army. The Legions had fought and destroyed a number of hostile races over the centuries, but because of all those victories, it was entirely possible that you could go through a tour of duty in the Legions without fighting a single major engagement if you weren't serving on the Shieldwall, because the other regions no longer bordered any enemies. This costs them dearly in the initial battles against the Vord.
 * A theme in Curse of the Wolfgirl is that the leaders of the werewolf clans have become complacent about the idea of Scotland being a fortress against werewolf hunters. Naturally the big set-piece battle of the book is in Edinburgh.
 * Humans on Earth in Dan Simmons's Ilium. It's taken to the extreme by the fact that they're not even in charge, but rather being baby-sat by a bunch of robots, so that they don't have to know how to do anything. By the end, they're having to learn how to fight again.
 * In Honor Harrington this is the job of The Solarian League. 5/6 of Human space is dominated by the league, with slow outward growth giving new systems entry via the Office of Frontier Security. No fleet Battles fought for 300 years, with no real wars fought since the League was founded. The Biggest, Most Powerful System Man ever saw. Ten Thousand Superdreadnaughts. But the political mechanisms running the league are ineffective. The politicians have no real power because the founders didn't want a real central government (think something like the US under the Articles of Confederation mixed with the EU and older Polish laws). The Bureaucracy has the real power, but is still pretty limited. The power is conserved mainly within families, subverting the democracy and merit requirements for politics. Any member system can veto actions of the elected government, so the Bureaucracy endeavors to make nothing real come up for votes. Because they are big and impossible no one minds this, despite this meaning their Navy is split in two, with the light elements mostly part of Frontier fleet whose job is to suppress pirates and those who'd rather not join the Solarian League, and the rest in the Corrupt Battle Fleet whose positions are on patronage. So bad is it, that sending out any report challenging any assumption the fleet runs on is career death. Of those 10,000 S Ds, only 2,000 are in service, 8,000 are mothballed (and some sold off piece by piece) and nearly all are several hundred years old and only periodically updated. A few are made each year mostly as politics and keeping the skills around. In their first real fight they lose dozens of S Ds to light fleet elements. Oh Crap.
 * High Ride and Janacek started pushing the Manticoran Navy down this path between Saint-Just's death and the restarting of the Haven War, despite Harrington and White Haven's best efforts to the contrary.
 * This is part of the premise of the Man/Kzin Wars. Humans have used a combination of social programming and chemical cocktails to remove humanity's collective balls. We get them back, though.
 * Saki's When William Came.
 * Mentioned several times about the United States and Britain in The Winds of War and War and Remembrance.

Live-Action TV

 * Commander Adama believed this of the Colonials, forty years after the Cylon War. And he didn't just mean in terms of military strenth and readiness to fight: he meant morally, as the Colonies had forgotten the reasons behind the war and their responsibilities to the Cylons. You know how this ends.
 * In the original series Doctor Who episode "The Invasion Of Time,'' the Time Lords take their indestructible force field so much for granted that they really have no other defenses (or at least none that are up to fighting ) Naturally, the force field gets breached.
 * Star Trek: The Next Generation was a good example of this. In the words of sfdebris, the Federation had grown arrogant in its beliefs; exploration was their main goal and they believed that they were prepared for anything. Then Q appeared and put them in their place, introducing them to the Borg, who proceeded to massacre the entire fleet with a single vessel.

Video Games

 * The Star Wars Old Republic has this pointed out at least three times in Knights of the Old Republic 1 & 2.
 * This is a major element of the Mass Effect saga. The Citadel races desperately want to believe everything's still going fine - the Rachni are a memory, the Krogan are irrelevant, the Geth have been defeated... and they refuse point-blank to acknowledge the return of the Reapers. Only the humans, energetic newcomers to the galactic scene, are prepared to acknowledge the existence and terrible threat of the Reapers... And that only lasts until the sequel, when humanity's increased influence on galactic affairs has led to them becoming just as complacent as the others.

Webcomics

 * Alpha in Akaelae comments that due to the council whittling away the space navy, he can't do anything to help Celina escape.
 * Dreamkeepers has it so that using your powers is grounds for exile. This is due to in part of the Nightmares, the reason for their powers in the first place, hiding for a long time and having double agents in the government.

Real Life

 * The Ur Example is from Herodotus' Histories, written in the fifth century BCE King Croesus asked Solon whether he was not the happiest man on Earth. Solon answered "Count no man happy until he is dead", and cautioned that fate could change for him. He pooh-poohed this idea... until after he had his empire utterly destroyed by Cyrus the Great.
 * Of course, there are a few differences between this and the modern trope: He was the one who went to war, after asking the Oracle of Delphi for the result of this, and being told that it would result in the fall of a great empire if he did. The great empire that fell? His own.
 * Often mentioned, especially during the 1960s and later, how the United States has become weak and decadent thanks to the "dirty hippies", so now we are in danger from the Dirty Commies.
 * This argument is coming into sharp focus once again due to America's repeated humiliations on the world stage (real or imagined). It was also part of the reason that Battle Hymn of the Tiger Mother caused such a stir in the US of A, with reports of declining education standards vis-a-vis the Far East.
 * This was pretty much a hallmark of the history of Central Asia, where a virile dynasty of steppe warriors would take over a corrupt or effete civilization only to become decadent themselves and be kicked out later by a fresh batch of nomads.
 * This trope is actually a rather accurate representation of typical human behaviour during eras of economic bubbles. For a simplified example, in Ireland, the 'Celtic Tiger' boomed from the mid-1990s to the late 2000s on the back of a quickly-expanding property market and the increase of professional workers spawned by the growing 'knowledge economy'. For the first time, Ireland was no longer considered a Third World country, and, in fact, had skyrocketed to becoming one of the world's wealthiest countries. However, in spite of the warnings of economists across the country, the bubble burst hard as it emerged that corruption was rife through both the banking institutions and property developers in the duraion of the boom, causing Ireland to fall billions of Euro in its national debt (which, although coinciding with the then-emerging global economic crisis, was nonetheless a separate issue entirely). Lower-level workers in both the private and public sectors, having grown accustomed to their new, more affluent lifestyles, were now facing mass pay cuts across the boards, while the toxic banks were being bailed out with money that would never be seen again (and, judging by the reluctance of the higher-ups to change their ways, to little effect). In short, the people (and, to a more worrying extent, the government) had grown reckless and careless with money, over-relying on credit for payments and making foolish purchases, only for it all to bite them later in the face of the current recession/depression.
 * The latter half of this story seems to be happening in every old-time Capitalist country. The USA, Greece, Spain, Italy...
 * According to the Muqaddimah, a 14th-century Arabic text by historian Ibn Khaldun, this is an important factor in civilizations' decline. The theory is something like this: Early generations of a city have a strong sense of community and an ability to defend themselves, because they're not far removed from dwelling outside a city. The later generations become complacent, relying on the city instead of each other, and either don't see a threat coming or can't deal with it. Changes in the rulership of Islamic Spain, in which a decadent dynasty of Umayyads was replaced by a group of religiously zealous desert dwellers from North Africa, were almost certainly an influence on Ibn Khaldun's theory.

Unsorted

 * In Spirit Fox by Mickey Zucker Reichert and Jennifer Wingert, the nations of a continent make peace after a war, going so far as disbanding their armies and having the priests announce that their respective gods have combined into a new pantheon and declared a new era of peace and prosperity, and that henceforth military preparations are unnecessary and an evil in the sight of the gods. Twenty years later, when nearly everybody's become comfortable, an invasion force shows up from the next continent over. After that, things happen just as the trope description says.