And he also told Tom that he thought Sonny was a bad don, but that he never thought Tom was a bad Consigliere.

But ... we have to consider what might only be a correlation. As Tom functions as Consigliere and then is actually named as Consigliere, the Corleone family fortunes decline. Was that just a confluence of events?True, Tom advised Vito that he should accept the Sollozzo deal. But, other than that, how was Tom an asset to the Corleones?

"Generosity. That was my first mistake."
"Experience must be our only guide; reason may mislead us."
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