Why was Michael still the Boss of the family in 3?

A man who desperately wanted to leave the criminal world behind so desperately, then why wasn't Joey Zasa the Official Boss of the criminal operations that were once crime family businesses and why was he 'The Supreme Court' of the Mafia Commission at this point?

Michael's power base in 3 is never credibly explained. On the one hand, Zasa commands what used to be the Corleone street operations in NYC (the "olive oil business"), as he told Connie and Vincent at his party. He "sold all his shares in the casinos," as Abbandando explained to the reporters at his party. And, after the casino shooting, he mutters, "Just when I thought I was out, they pull me back in."

On the other hand, Michael is, as you point out, "the Supreme Court" of the Mafia; has enough power to prevent Zasa from rising in the Commission; presides over a Commission meeting in AC, and distributes profits from some unknown source. He couldn't have maintained that much clout among top organized crime figures without having his own organized crime power base.

The main weakness of GF III is the script, and this is an example of that weakness.

That and some of the casting decisions. Other than that, it's a fine edition to the Godfather Saga!!

I can see why Robert Duvall passed on III. I can still watch III, with some fast forwarding employed.

One of the biggest flaws in part 3 is the character of Mike. In the first 2 films he goes from basically a good kid who wants nothing to do with the mob to a ruthless cold blooded mob boss who is obsessed with gaining power,money,and dominance over the other families. In Part 3 they tries to go bac to the beginning and make mike removed from the mob but it doesn't work.

TB, as I've posted elsewhere, in III I see Michael as analogous to Tony Accardo in Chicago. Tony bossed the Outfit for so many years, then turned it over to Giancana. But Tony never lost his influence and ended up deposing Giancana. I think that Vincent's "Supreme Cousrt" statement about Michael's influence and the efforts of Michael's enemies to rid themselves of it sums it up.

I don't think Michael really wanted out all that much.

I think he wanted out of the day-to-day dirty work (thus his willingness to allow Zasa to rise up in the pecking order).

But he still obviously felt entitled by his experience to wield a lot of clout with The Commission.

He knew he couldn't do that for long if he really did get out.

I agree. Michael was addicted to power. His whole life after he returned from Sicily was geared toward holding the power that comes with being a Don, and trying (desperately) to be "legitimate" at the same time.

As TB points out, it is in only some very unusual circumstances and instances that one eschews one's endemic personality and habits. Michael's diabetes and guilt may have given him significant pause to reconsider his life choices, but enough of the real Michael was still there in III.

GFIII full reveals what a paradox Michael's character is. He wants it both ways...he will not give up his nefarious power, yet he is always seeking redemption. Its an impossible situation that tragically ended on the steps of the Opera house.