Season 1, the Feds have Junior on tape talking about clipping Tony. Granted, the conversation is with Livia, but when you consider there was an attempt on Tony's life after that you would think the Feds had a pretty good murder conspiracy case.

Which begs the question, why didn't the Feds jam him up on a murder conspiracy? At the age of seventy, he would have been looking at the rest of his life in the can. He may have flipped.

The case they put together should have stuck in theory, they mishandled it. Including an attempted murder charge would have weakened the case not enhanced it.

In this situation they put together what they could prove, they weren't charging Junior with all they knew of him, just what they knew would stick (or so they thought)

Tony refusing to testify would doom the case. That's why the FBI showed Tony the tapes in the first place. Junior didn't say anything about the hit on the tapes either. All he said was "If this is true, blood or no blood, I mean, I'm the boss for Christ's sake!" Even within the context of the conversation, that isn't a clear indication that he's going to kill Tony.

No chance would Junior have flipped,