However, there is language in the novel and film explaining the Corleone reason to murder Sollozzo.
My point is that it was bad reasoning, because with or without Sollozzo they'd try to murder Vito.
No, I think they knew Vito was no longer capable of being a full time Don. He was no longer wirth the expense and bloodshed. Everyone knew Sonny was running things, and they also knew Sonny was a bad don. Even after Sonnny died and Michael tried to buy Moe Green out, Moe was going on about how Vito was sick, and how the Corleones were being moved out of New York. The consensus was that from the time Vito was shot going forward, the Corleones were perceived as weak.
