Madara Summonded the ninetails on the village 16 years ago because he knew that it would cause the others to constantly watch/moniter the Uchihas, and he knew it would cause the Uchihas to rebel against Konoha, he wanted another war to start, But what Im stuck at is this, If he would of simply killed Itachi, A war would have started, Is that not what he wanted? So why did he help kill the Uchiha clan and prevent a war?