In the Las Vegas scene, the novel is very clear about Michael: He had not once raised his voice but his words had a sobering effect on both Greene and Freddie.

Why was Al Pacino playing Michael aggressively? To me it makes no sense, especially when he's already almost the Don.
Pacino's way of acting? Or FFC's order?

D, I think it was a hint of what Michael was capable of. It was a preview of what we observed of Michael in II which was the angry Michael. Of course, II was not planned while I was being filmed, so I think it was just Pacino's portrayal, but probably with a little coaching from FFC.

I think the scene called for an aggressive stance from Michael, considering what Moe had said. Michael was talking business.
Moe came at Michael saying he was doing the Corleone's a FAVOR- which he was not.
So Michael took the angry, aggressive stance by emphasizing that there was a business deal in place regarding the bankrolling of the casino in exchange for the guarantee of Fredo's safety (and I'm assuming his education in the hotel-casino industry).

Michael's aggressiveness was warranted and necessary to emphasize that NO favor existed. It was actually insulting to Michael that Moe would act as though Michael didn't know the details of the deal that was made and that Michael was coming at him from a position of weakness.

Michael had to affirm to Moe that the Corleone's were negotiating from a position of strength.

Of course, Moe would very well have seen Michael's aggression as that of an "animal backed into a corner", which is why he rattled off all the information about Barzini's deal with him, trying to establish his position as stronger than the Corleones.


And perhaps that was Michael's plan all along- to gauge the reasons why Moe Green felt emboldened enough to slap a Corleone around and straighten him out.

Was this Pacino's or Coppola's decision? I can't say. I didn't see any direction for it in the script. It might be one of those things where the actor asks, "What's my motivation in this scene?" Or a collaboration between Pacino and Coppola. It seemed there was a lot of behind-the-scenes discussions and collaborations between Coppola and the actors.

Which is what usually happens during the making of a film.

True. But some directors are more open to discussion and input from the actors than others.

Watching that scene again, I think two things:

1) As stated above, Moe is all "You want to buy me out? I did you a favor by taking Freddie in". Michael counter this with "You took Freddie in because the Corleone family bankrolled your casino" to reinforce the fact that this isn't him cashing in a favor, it's a business meeting. He feels insulted that Moe would think he's calling in a debt.

2) I think he wanted to gauge why Moe would be so against the idea. I don't remember how this scene plays out in the novel, but maybe the anger was to goad Moe into openly stating that he wasn't a friend, since right after Michael raises his voice Moe goes into his rant ("First of all, you're all done. The Corleone family don't even have that kind of muscle anymore...") that name drops Barzini.

For me this moment is out of the line of Michael's development to the Don. In the novel this is shown beautifully: Michael dominates the situation by his mere presence and the Corleone stare. After all, Michael calms down: "Think about a price" is almost like "My offer is this - nothing" in GF2.

Michael is doing several things at once in this scene (in the film, I am not talking about the novel). First, the obvious, he is making a frontal assault on Moe who he probably already knew was trying to make a deal with Barzini. Second he is sending a message to Moe and indirectly to Barzini that the Corleones are planning to leave New York. Moe reacts as expected, going on about how this is an involuntary move, a move made necessary because the Corleones are being run out of town. Third he is guaging what the word on the street is about the strength of the family...they still think the Corleones are weak...exactly what Michael wants them to think. Fourth he is testing the loyalty of Tom and Fredo to him. When Moe appeals to Tom, he is having none of Moe. He says the Don is semi retired, and the only person who can answer questions about the family is Mike, who is now in charge. Fredo on the other hand exposes himself as willing to say what he is thinking about the family business to people outside the family...even take sides with them. In a great foreshadowing of things to come Michael tells Fredo not to take sides against the family again ever....."ever." That second "ever" is a warning to Fredo that despite their relationship as brothers, Michael is boss, and if Fredo messes with this ever again he is in big trouble. Going to the whole issue of "should Michael have killed Fredo" in II, we need to look at this scene, because Fredo's deal with Johnny Ola (who worked for Roth, Greene's mentor who got word of Fredo openly challenging Michael)becomes the second, not the first time he crosssed Michael and threatened the family. Fifth he is laying thr groundwork for the surprise hit on the heads of the five families. This move on Moe is not supposed to be anything more than an offer Moe should have accepted. By making this offer Michael is reassuring Roth (who we don't know at this point in the saga) that he has no interest in anything Roth owns in Vegas, just what Moe owns, and thus signaling Roth that whatever he is up to is not a threat to Roth's interests. The last thing he needed after killing everyone else was Roth on his back (at least for the time being). Finally Michael is formally announcing to the world that he is the head of the family. Why? Probably to make his enemies think the family has officially gone to hell which will make them underestimate him.

DT, what does your analysis have to do with the question about Pacino's acting?
Oh, and not only we didn't know Roth at that point. Puzo and FFC didn't either.

If I may answer on behalf of DT: he's illustrating what Pacino might have been trying to achieve through his acting and convey to the audience.

What Olivant said.

You'll notice in the book that Mike seems less sure of himself in that meeting. When Moe starts talking to Tom, after arguing with Michael, Michael jumps back into the conversation and lets everyone know he's running the family.

In the movie, he just sits there quietly while Tom explains that Michael is in charge now. Michael is complete control, he knows it, and he doesn't feel the need to say any more to Green then what he's already said.