I am not 100% sure about this and Turnbull is causing me to reexamine my position on this. But I can't get past how angry Michael is and appears to me to be directing his anger towards Frankie when he gives his "in my house, in my bedroom where my wife sleeps" speech. Also, I do not consider Frankie's turning states evidence at the Senate investigation as Frankie plotting. He was arrested and was being coerced to testify against Michael. He was VERY reluctantly testifying and I think he would have defended himself a little bit when Tom Hagen and he were having their cigar conversation. Tom, "When a plot against the emperor fails..." Frankie makes no reply to Tom's accusation.

Also, consider this...wouldn't it be a perfect scenario for Roth if he could actually get Frank Pentangeli to hit Michael for him not just make it look that way. Michael was already expecting trouble from Frankie.