Vito had to good sense to realize he would lose political and judicial support if he went into drugs the same way he went into women, gambling and labor unions, but Sonny did not.
But did Vito really lose any support by going into the drug trade? We tend to take that as an article of faith, but is there any evidence it actually happened?
When Vito realized he couldn't hold off the drug trade any longer, he quickly agreed to provide the very protection he had just said that he wouldn't be able to provide for the drug trade. We're given no reason to think that he was unable to provide it.
In fact, while the judges and politicians on Vito's payroll refused to come to Connie's wedding, Michael - after years of involvement in the drug trade - had a
United States Senator give a speech in his backyard.