The quote that Plaw talked about and that SC posted from the book answers the question. But let's put the book aside for a moment and just go by what we see in the movie itself. In watching that scene I've always took it that Michael was not 100% sure that it was Carlo who set up Barzini. Michael twists the question to Carlo. If Michael had asked Carlo straight out " Did you set up my brother?" he would have shown his hand to Carlo, allowing Carlo to see that there was doubt in Mike's own mind and by seeing the doubt it would have given Carlo an opportunity to deny that he had set up Sonny, with nothing to lose by lying. But by Michael phrasing the question the way that he did to Carlo " Now who approached you, Barzini or Tattaglia?" it tells Carlo " I already know that YOU set my brother up, so there is no denying that, but now I need to know who approached you to set my brother up?" Asking it this way is not showing Carlo that he (Michael) has any doubts that Carlo set Sonny up. Therefore Mike does not let Carlo see his hand and that does not allow Carlo the opportunity to deny it. Phrased in tht manner it makes Carlo confess and at the same time it erases any doubts that Michael had in his own head.


Don Cardi