"The thinking, clearly, is that the chief will retire in June," said a person who has participated in these discussions. "The question is, of course, is whether he will be able to endure until then."

No one, from the most high-level administration officials to those on the periphery of the discussions, agreed to be quoted by name, both because the discussions are confidential and, just as important, because it is considered unseemly to discuss someone's serious illness.