Murray Humphreys. Why? Because he was one of the first mobsters, if not the first to popularize the "taking the Fifth" to avoid self-incrimination. He was a mix of menace and smarts. The Hump was able to stay at the leadership level of the Outfit for years and along with people like Costello is probably the best real life example of a wise consigliere.

Humphrey's Oklahoma house


"When the snows fall and the white winds blow, the lone wolf dies but the pack survives."
Winter is Coming

Now this is the Law of the Jungleā€”as old and as true as the sky; And the wolf that shall keep it may prosper, but the wolf that shall break it must die.
As the creeper that girdles the tree-trunk, the Law runneth forward and back; For the strength of the Pack is the Wolf, and the strength of the Wolf is the Pack.