during the meeting with sollozzo sonny makes the mistake of showing absolute interest into what sollozzo and the tataglia family has to offer. sollozzo sees that there is a possbility for the corleone family to have a partnership in all this, that is if don vito corleone is out of the picture. sollozzo's attempt on don corleone's life is done in hopes that with sonny taking over the family, there will be a successful partnership in the future.

as hagen said, the rest of the five families have gone along with sollozzo and the tataglia's in hopes of preventing a full scale war, and now the corleone's are outcasts. michael understands that the only way to save the corleone family is to eliminate all their threats and enemies

In my home! In my bedroom, where my wife sleeps! Where my children come and play with their toys. In my home.