Good point SB. The whole idea of murdering Vito who was the golden goose when it came to political protection and influence makes no sense. Of course, this has been discussed quite a bit in other threads. But the novel states emphatically (and one can definitely infer it from the film) that Vito's political influence was a function of his personal relationship with politicans and was not, in all likelihood, transferrable to Sonny or anyone else. So, if politicians were not inclined to follow Vito's lead on drugs, why would they be inclined to follow anybody's lead?

"Generosity. That was my first mistake."
"Experience must be our only guide; reason may mislead us."
"Instagram is Twitter for people who can't read."