Sollozzo made Vito a big offer for police and political protection: 30% of his profits--"in the first year your share would be three/four million. Then it would go up." Vito refused. By the time of the Don's Convention, Vito was in a weakened state and had to give in. His share? As Barzini said, "Of course he can present a bill for such services..." In other words, Vito was reduced to being in the rent-a-judge business.
Vito went along because he had to in order to guarantee Michael's safe return, and also to reinforce his "weak" appearance. Michael presumably went along with the rent-a-judge arrangement for the same reason. But, after the Great Massacre of 1955, I'm wondering what Michael's position was on drugs. I can't see him walking away from a source of income on "moral scruples." But I also don't see him retaining the rent-a-judge arrangement since he was now the most powerful of the Dons. What do you think his attitude and arrangements were?