Well put, dt. Of all the many plot weaknesses in III, the weakest are: why did Altobello turn against Michael, why did Michael want Immobiliare, and why was Lucchese against him?
Weakest line? Where to begin? How about "Our true enemy has yet to show himself?"
I don't think those are glaring plot holes.
Archbishop Gilday - quite the manipulator himself - makes clear why Michael would want Immobiliare - wealth and legitimacy:
This deal with Immobiliare can make you one of the richest men in the world. Your whole past history, and the history of your family, will be washed away. If Michael is taking over, someone's interests were pushed aside. Apparently those were Lucchese's.
As for Don Altobello, his motivation is less explicit. But he does express concern that Michael is not sharing Immobiliare. And he apparently has a long history with Lucchese (according to Don Tommasino, Altobello "kept the peace" between the Americans and the Sicilians), who must have made it worth his while to turn on Michael.
Weakest line: "I'll always love you." Hands down.
