He screwed us over big time ladies and gentlemen, and I of course am referring to the infamous blunder in failing to kill Kabuto in the hospital in the Destruction of Konoha Arc in Part I. Think about it, that was THE definitive perfect moment to end that bastard's life, there was no one to guard him, no insane ability to protect him, just him and Kakashi. His mother couldn't really kill him, because really, he was still just a child. When he was in the Forest of Death he was masquerading as a good guy. When he was fighting Tsunade, Jiraiya and Naruto, he had Orochimaru babysitting him the whole time. When he appeared on the Bridge of Tenchi, he was also closely being watched by Orochimaru. When he gave Naruto and Yamato the Akatsuki infobook, he convincingly came forth as a friend. When he approached Tobi, he had his nuts in a vice because of the Edo Madara summoning. And truly, from probably before then, and that point forward, he was simply too powerful to be defeated, considering his assimilation of Orochimaru and the Sound Five, also his assertaining of the Senjutsu. So Kakashi, when you failed as a Jonin to stop that bastard, you really goofed. You could've saved the shinobi so much trouble.
P.S. Don't say that they would have summoned Madara anyways by means of Nagato because even taking that into consideration, all of the contributed Edo Tensei bodies, and Yamato's capture stimulating the creation rate of White Zetsu Clones rapidly accounted for a vaaaaast majority of ASF casualties aside from Madaras.
P.P.S. Don't say Kabuto could have overpowered Kakashi at the time you raving fanboys, keep away from this thread with your drivel.
P.P.P.S. Anyone who mistook this a "seeerius biznis" type thread is a dumbass really. I was just using some basic syllogisms to come to a funny conclusion.