I don't believe Desjardins was behind the murder of Nick Rizzuto. Otherwise Nick could have already been killed as soon as 2007. There was nothing to gain for Desjardins to take out Nick. Desjardins as a French-Canadian, could have never taken over the Italian organization. He was already running his own things with his boys when Rizzuto was still alive. Montagna however, needed to take Nick out of the way to take over his organization. But it was mostly a symbolic murder as Nick had little power left. Montagna then likely wanted to take over everything in Montreal and regarded Desjardins as an obstacle. That is when he tried to take Desjardins out. For Desjardins it was kill or be killed and he took his changes. Bear in mind that the Cotroni organization was also at war with French-Canadians in the 1960s and 70s with bodies on both sides. This was when the Bonanno family's influence in Montreal was still strong.