Not sure who you are alluding to eurodave but I think that Desjardins initially respected Montagna and I doubt that he manipulated him into thinking that he would become the leader of Montreal. I think this was never the arrangement they made. Montagna was probably going to reorganize the Bonanno group while Desjardins and his group would remain independent. I base this on the fact that Desjardins texted Mirarchi that he had trusted Montagna and that the latter had betrayed him. I think that if anyone manipulated Montagna it would be the Arcuri brothers. It would be to their benefit if Montagna became the leader and perhaps they believed that they could influence him. This makes me think that they may have been the true instigators of the war, after all, they had introduced him to Desjardins knowing that he and his boys were necessary in order to go up against what was left of the Rizzuto group. It was the elder Arcuri who was or felt like being passed over by the Rizzutos after Violi was clipped. The Arcuris seemingly were never truly allowed in the Rizzutos' circle of trust like the other paesani from their village.
Sorry I didn't specify per say.
What I meant to say is that certain people including the Arcuris and others close to him , manipulated motivated and pumped him up, using him to a certain extent to further advance their own agendas.