Sonny's indiscretion certainly encouraged Sollozzo to think that there was a split in the family that he could exploit. But I stop short of saying that Sollozzo wouldn't have tried to kill the Don if Sonny had been silent. Sollozzo was intent on getting into the drugs business. He calculated that he could kill the Don and make a deal with Tom and Sonny for the remainder of the Don's political assets. He probably figured that Sonny would try to kill him in revenge. But, with the Don dead, much of the Corleone Family's strength would have disappeared. Sollozzo figured that if he was careful and survived, over time Sonny and Tom would see that there was no percentage in holding a grudge, and that they should make a deal with him.