In the end of the novel, Kay leaves Michael and returns to New Hampshire. Tom Hagen goes up to talk to her. She asks him about Carlo's death, about the fact that Carlo had turned it around, was a good husband and father now, never beat Connie any more, was a good worker, etc. She asked why he couldn't be forgiven, and Tom says, "In this world, he could be."

Fredo would always be a danger, especially after his rampage in the boathouse revealed the depth of his resentment toward Michael. Michael couldn't let Fredo live, because he would always be a threat to the Family and the family.

Sure, it bothered Michael. Yes, it was the one murder that plagued him, but I still think that if he had the opportunity to turn back time, he would have done it again.