Apologies if this has been discussed before but I just thought of a question... Why wouldn't Michael take Pentangeli into strict confidence and let him in on the ultimate plan? Wasn't Frankie the most trusted Corleone Family member in New York at that time? I am interested to hear the main reason why? Michael's fear of plan leaking? Obviously at the top of the list but why else? Thanks.
Michael realized Frankie's limitations. Frankie even described himself as not having a mind for big deals. He was too spontaneous; Michael realized that too much information could overwhelm Frankie, or be misinterpreted by him, or not register with him at all resulting in unintended consequences.
