The Federation has been fighting against The Empire for a long time. They've not made much headway, nor have they managed a decisive strike. The one day... The Empire is gone! Or maybe suddenly suing for peace or otherwise in no shape to keep fighting. There's a hole in the flag; the constituent territories are declaring independance left and right, and someone else is in charge of whatever's left. Perhaps The Rebellion worked--or perhaps an Enemy Civil War destroyed the nation. Perhaps there's been a Succession Crisis and nobody's won. Or perhaps there's been a Velvet Revolution. This is one cause of Last Plan Standing. This is when one side of a conflict simply falls apart from within.
- In the 'modern' (post-1991) Star Wars Expanded Universe the Empire takes years to collapse (and even then it ends up a Vestigial Empire rather than ceasing to exist.) On the other hand the Marvel Star Wars comics of the 1980's do follow this with the Empire collapsing completely after the Battle of Endor.
- In the 1999 adaptation of George Orwell's Animal Farm, as the pigs exert tighter and tighter control over the farm and adopt more human-like mannerisms, Jessie the dog convinces the rest of the animals they should abandon the farm for their own safety. They would later return to the farm and discover that the pigs' excesses had slowly done themselves in.
- Star Trek VI: The Undiscovered Country deals with how the Klingon Empire suddenly asks for peace with the Federation following the destruction of its moon, Praxis, because it was a major energy production facility and because its destruction is wreaking havoc on Qo'noS.
Hello, Unknown Troper. You'll need to get known to lend a hand here.