Vicious Cycle
The first two Avatar assassination attempts were by Fire Nation, and Zuko dealt harshly with the assassins and with the nobles who'd hired them. But the third one: "Southern Water Tribe," Sokka announced grimly. "Dad kicked this guy off his crew years ago."
"Water Tribe?! B-but ending the war saved them!" Aang protested. "Why…?"
Zuko suggested, "Maybe because you refused to allow anyone to take revenge on the Fire Nation, beyond war crimes trials for the very worst offenders."
"I admit, most Water Tribesmen believe in revenge," Sokka sighed. "And the next Avatar in the Cycle would be Water Tribe…"