One must admit that Mr. PC is very shrewd because-
1) At the earliest opportunity he shifted from finance to home affairs ( although he loves finance for reasons need not be mentioned) & saw to that CBI safeguards his interest.CBI has not not produced any paper which pointed to implicate him;2) Unlike other poiltician he has not spoken to media at all to avoid problems in the future 3) After leakage of finance ministry letter to P.M puting blame on him, he said, he would comment ,once the P.M. was back from foreign tour, but , heard nothing from him so far.- Is he very cunning?
But he is not Alibaba
Regarding his shrewdness, we have to accept it.
Miserably he failed to give comments when Raja fixed(?) the price for Spectrum even though he was fully aware of the pros and cons
He was forced into the Finance Minsitry after the fiasco of a HM we had in Shivraj Patil, immediately after the Mumbai Terror Attacks. As is known to everyone, PC's interest lies in Finance Ministry. He was known to be a good administrator and PM wanted someone to placate the mood of the public after the attacks. So he brought in PC to the HM.
To my knowledge, I don't think CBI reports to the Home Ministry. It comes under the PMO. Check this out if I am right.
There could be so many other interests that could be protected by protecting the HM. Hence the PM and Government defends him.
PC is a much educated man, a top lawyer himself, and knows well to do or to not to certain things in certain times. That makes him somewhat different from others in Centre.