Remember that, just after Michael told Tom he wasn't a wartime consigliere, he added, "Besides, who's a better consigliere than my father?" Then his father died and he needed Tom as his consigliere.

Michael was, indeed, the master manipulator. That's what he did to Tom after the Tahoe shooting, giving him all that crap about being his "brother," etc. And Tom ate it up. But, after he returned from Havana, Tom was the guy who "couldn't give me a straight answer anymore."

In III, Michael laments, "Just when I thought I was out, they pull me back in." Tom could have said that several times in GF and II, substituting "Michael" for "they."