Much has been written and discussed about why Michael told Fredo in advance that Roth tried to kill him in Tahoe and that he was to be assassinated later that night. Perhaps it was an act of superb cunning Michael's part. Michael already suspected Fredo, but it was not confirmed until the offhand comments at the Superman show. What was clear was that Frdo was a nervous wreck, and already showing anger at Michael, remorse that he couldn't be "more like Pop," and that he didn't marry a woman like Kay (As an aside given the gay theory in that awful book, you could take Fredo's comments two ways...that he didn't marry a woman like Kay OR he didnt marry a woman. Like Kay. ).

Given that Michael suspected him, and given Fredo's agitated state of mind, it is possible that Michael realized by telling Fredo these things it would actually make Fredo even more nervous about having any contact direct or otherwise with Roth or his people. In other words his disclosure was a sort of Sicilian cunning head fake which actually deterred Fredo from contacting Roth. In orther words a clear case of keeping his enemies closer.

Well, dt, as you said, this is one of the enduring mysteries of II. And, you advance an interesting and supportable theory. But, two things stick out:

First, if Michael really suspected Fredo of being the traitor, he took an incredibly dangerous risk in letting Fredo know that "Hyman Roth will never see the New Year."

Second, Michael is genuinely devastated when Fredo makes his fatal gaffe at the Superman show. You might argue that the devastation was that Fredo confirmed what Michael had already strongly suspected. Or, I might argue that, until that point, Michael didn't think Fredo was an active part of the conspiracy. (In Tahoe, I think he implied to Tom that he couldn't trust Fredo to run the family in his absence--not that he thought Fredo was the traitor.)

The hangup for me (and probably others) is those searching looks Michael gave Fredo when Fredo asked who else was in Havana, and when he introduced him to Johnny Ola. If those looks implied suspicion, we go back to square one: Why, if Michael suspected Fredo, would he tell him when he was going to have Roth killed?

DT and TB, I don't think Michael suspected Fredo at all. TB, you cited how devastated Michael was to learn of Fredo's culpability at the Superman show. True. On the other hand, I don't see Michael's facial expressions when Fredo arrives with the money as searching at all. In fact, it is Fredo who brings up the subject about knowing anyone in Cuba, not Michael. I don't think that Michael knew anyone else in Cuba besides Roth and Ola (except for those who would help him dispatch Roth), therefore there would not be anyone else's names to bring up in response to Fredo's question.