Answer: Vito Corleone (Marlon Brando)
In this scene rival mob boss Sollozzo is attempting to get the Godfather to help finance his narcotics business. He says, "I need, Don Corleone, those politicians that you carry in your pocket, like so many nickels and dimes." But the Godfather turns him down and says, "It's true, I have a lot of friends in politics, but they wouldn't be friendly very long if they knew my business was drugs instead of gambling, which they rule as a harmless vice." Then Sonny says, "Aw, you're telling me that the Tattaglias guarantee our investment?" Clemenza and Tom realize Sonny's faux pas and look at each other in surprise. After Sollozo leaves the room, Vito Corleone says this quote to Sonny.