We have been talking in another thread about Vito's slip up in the Sollozo business, but I am wondering if it was Sollozzo and the other families who ultimately "slipped up."

As I understand it, Sollozzo needed $1 million start up money and he needed Vito's police and political connections.

As Tom and Sonny both recognized drugs was the next big thing, and that if the Corleones didn't get into it the other families would, and in time marginalize the Corleones.

After Vito told Sollozzo "No," why couldnt Sollozzo go to Tattaglia, Barzini and the other families and get the money from them? Certainly Vito did not have a monopoly on police protection...Sollozzo already had a Police captain in his pocket, and as the drug trade grew, he could have bought off more cops, and all the while Barzini and Tattaglia could continue to chisle on Tessio and Clemenza's territories, as they later complained they were doing.

This scenariou would have isolated the Corleones, hurt them financially, and in time reduced their political muscle because where corruption is concerned you always follow the money anyhow.

Furthermore they all had to know that The Don was getting on in years and that Sonny would either come around to their point of view, or become a target himself leaving Fredo the heir apparent.

So the question is, did Sollozzo and all the other families really need the Corleones' cupport to make their drug operation work?
So all in all, if the Don was already "slippin" why did they need the Corleones at all?