Originally Posted by The Batman
Batman did win in TDK.
His goal throughout the film was to support, protect, and help Gotham City. Supporting Harvey was a means to that end. Joker corrupting Harvey was not about turning Harvey, but about breaking Gotham's spirit. As Batman prevented that by taking blame for Harvey's crimes, He saves Gotham's soul and therefore did not lose in TDK. At worst, Batman suffered a pyrrhic victory.
Not only that, but in TDKR Gordon plainly states in his letter "Batman did'nt murder Harvey Dent, he saved my boy."
That's true I misspoke. He won. But it cost himself a chance to free himself. The Joker at the end took a victory. Batman suffered a loss of sort. Batman won by dragging a boulder chained to his back. But TDk did a better (especially with it being a sequel) allowing Bats to go out with honor.
In MOS he won but it was not a clean fashion. I see it to be a pyrrhic victory as well. It cost him to win. It agony to win like that. And he did not fly off to victory.