I think the book fleshes out that Sonny was ruled out because he has a wife and kids unlike Michael then but now if he is in the same boat No doubt dilemma!
In the novel, Sonny says (of killing Sol and Mac), "I could do it." Tom dismisses this immediately. "Solozzo wouldn't let you near him if he had 10 police captains. Besides, as the acting head of the family, you can't be risked."
Ntra la porta tua lu sangu � sparsu, E nun me mporta si ce muoru accisu... E s'iddu muoru e vaju mparadisu Si nun ce truovo a ttia, mancu ce trasu.
