There have been recent threads considering the "what if" regarding different matters. While it is better developed in the novel, it is still quite clear in the film that Sollozzo was trying to ascertain whether anyone from the Corleone Administration disagreed with Vito's decision to pass on the proposed drug partnership. In the novel, Sollozzo tried by asking two questions, searching the facial expressions and answers of everyone in the room. While the first question failed, the second question reeled Sonny's greed/curiosity to show that Sonny disagreed with Vito's decision. I'm paraphrasing here, but essentially the novel said it was here that Sonny Corleone made an unforgiveable lapse in judgment. By showing that he had interest in the proposal nixed by his father, Sonny gave Sollozzo leverage. Sollozzo saw that the other members of the Corleone Family were horrified by Sonny's comments of openly disagreeing with his father.

Had Santino kept his mouth shut, and assuming no other members of the Corleone Administration outwardly displayed a difference in opinion from Vito, then would Sollozzo have felt that he could have made an attempt on Vito's life? My opinion is that Santino's gaffe made it easier for Sollozzo to justify killing Vito, but that Sollozzo would have tried regardless (provided that Vito's answer was still "no.")

Sollozzo viewed Vito as an old-timer, a "Mustache Pete," who stood in the way of progress for the more "modern" Mafia, for which Sollozzo definitely considered himself. It may have been tougher to convince the other Families to go to war against the Corleone's without Sonny's gaffe, but as a matter of pure business, I think that at least the Tattaglia Family was ready to fight on Sollozzo's behalf against the Corleone's - with or without Sonny's comments. One of the underlying "principles" of La Cosa Nostra is simple: to make money. Drugs was an excellent opportunity for the Tattaglia's to make money far beyond their income from prostitution.

I also think that despite Sonny's comments, Sollozzo took Vito's "no" as an insult. He needed Vito's political influence to make his drug carriers less likely to become informants if arrested. None of the other Families had anywhere near the political influence that Vito had accumulated, so Vito's cooperation was vital to the long-term success of the drug operation. Without providing his political assistance, Sollozzo felt that Vito was inflicting harm and impinged on Sollozzo's ability to earn a living. As the novel stated, Barzini even described Vito's "no" as an act of aggression.

Your thoughts?