Your point is well taken Evita. I've often wondered what Vito was thinking when it came to "Senator Corleone,Governor Corleone". for Mike.

At that level of public service,it would be virtually impossible for Michael to have any plausible deniability concerning the racket side of the Family. Perhaps the plan was to move Sonny into semi-legitimate ventures,i.e. unions,waste management,construction,etc,while letting the rank-and-file soldiers run the "blue collar" side,while collecting a piece without actually getting involved in the day to day operations.

Sonny would never have the intellect or temperament to rise above the basic leg-breaker level,so maybe Vito figured,"we'll just keep him as low profile and out of the spotlight as we can". However knowing Sonny,I think it would just be a matter of time before he sucker punched the Mayor.

At least,that is my two cents.
This is why I love this Board when it comes to the GF trilogy.
There are so many nuances,forks in the road,and even rabbit holes to keep us discussing,speculating,thrusting and parrying for another 50 years !