There is always one more battle.
No matter how total the victory, no matter how much is gained or lost, there is always that one last battle to be waged.
Sometimes it's to mop up the stragglers from the formerly last battle. Sometimes it's to consolidate new holdings, or to shore up old ones. Sometimes it's just to send a message, to prove your superiority.
But often it's to silence that voice. It's a general, or a politician, or someone in the media, there's always that voice egging on the other side.
Telling them that there's just one more battle...