Michael's business with Roth was about getting his hands on Roth's Havana gaming empire. That was the basis of his meeting with Ola at Anthony's party. Though Roth planned to have Michael killed after that party ("Plan A"), he would have told Michael all along that he'd have to come to Cuba, meet Batista and get his ok to succeed Roth--and hand over $2 million. That tale would have been a credibility-builder to relax Michael and make him focus down the road--not on the possibility that he'd be whacked before then. That's why Plan B was so brilliant: it was a perfect backup in case Plan A failed.

As for Geary: I believe he wasn't as dumb as he seemed. I think that, as a member of the Senate subcommittee, he had to know that they were holding Pentangeli as a surprise witness against Michael. His question to Cicci--did he get direct orders from Michael Corleone or was there always a buffer in between--was designed to get Cicci to reply: "I never talked to him," which would make Michael think he could get away with lying under oath rather than pleading the Fifth Amendment. I believe that Geary did it to avenge himself against Michael setting him up with the hooker murder in Fredo's brothel. All that BS he said at the hearing about his fine, salt-of-the-earth Italian-American constituents was designed to make him look like he was on Michael's side.