I think assuming the war in Montreal is just a simple breakdown of Sicilians vs Calabrians is naive, but I don't think it's too far off. Some educated guessing here:
* The Rizzuto/C.untrera-Caruana takeover of Montreal was backed by more powerful groups in Sicily than we realize (not just their families in Agrigento). Possibly they were backed by Toto Riina and the Corleonesi in order to have strong allies in North America outside of the Gambinos.
Leonardo Caruana was killed by the Corleonesi in '81 for opposing them so that may very well be indicative of their allegiance given the fact that the Rizzuto and Caruana-[BadWord] families were very close.
I'm now hypothesizing that the Rizzuto group was recognised as an independent group when Vito returned to Canada, but that the Bonannos were allowed to continue to operate in Montreal.
