AND THAT DOESN'T MATTER!!!

Gangster or not, Michael should not have killed Fredo. Fredo never intended for Michael to be killed AND Fredo would never be a danger again. The traumatic mistake of trusting Roth almost cost Fredo everything. So relieved to be forgiven at Mama's funeral, Fredo would from here on report back to Michael if an enemy (or friend) so much as said hello to him.

But that's only the half of it. Michael by this time viewed everyone as a businessman whose loyalties were based on business. Everyone he dealt with was a criminal. He saw things in black and white: You were either a traitor or not; you were either with him or against him. But there was more to a person than being a businessman or a criminal. Michael turned a blind eye to all shades of grey, all the complexities and dynamics in his and Fredo's relationship. He completely erased from his mind the human face of the issue.

And that was a mistake. He should have preserved a shred of humanity (mercy, sentiment, whatever you want to call it). He needed this to function as a person, even if he was in the mafia. He was still a father, a husband, an uncle, etc., after all. If there was ever a circumstance where it was right NOT to act like a gangster for a change, this was it.

We are dealing with Fredo here. This is not the head of a rival family like Barzini. This is not a big time player like Hyman Roth. This is not a professional conniver. This is not a paid assassin (he can't even hold a gun, let alone shoot one).

If we're debating whether Michael was justified in his own mind for killing Fredo, then we have a pretty empty debate. Michael can think whatever he wants in his own mind: Fredo could sneeze in his direction and he could deem that as valid grounds for killing him. But let's view this as objective people who are not impaired by Michael's paranoia, blindness, ego, and loss of integrity; and I hope some of us (most of us?) will conclude that Michael was not justified in killing Fredo. He should NOT have judged him by the confines of his mafia world, but by the standards of his familial world, which is a more normal and decent world ... And this was a world Michael really needed to keep one foot in, just as Vito had.