Moe was small potatoes. Had Barzini's attempt to kill Michael and become the big cheese been successful, he would have never kept his end of the deal with Moe Green.
So Barzini may have not viewed Michael's move against him as any kind of threat to him. In fact Barzini probably figured, "good, Michael Corleone has done my dirtywork for me." Barzini's thinking was probably that since Michael moved Moe out, now all he had to do was take Michael out and he'd automatically be the Capo Di Tutti Capi and the casino that Michael had taken from Moe would become his (Barzini's) without his having to take out Moe Green himself. His thinking probably was that "The Corleone's have given me one less thing to worry about by killing Moe Green."
Remember that at that point, in Barzini's mind, the Corleone's were powerless. At that point, Barzini had already began seeing himself sitting on the throne.
That's a great post, DC. However, isn't it mostly conjecture on your part? The novel does not mention Barzini or any of the other New York families wanting to move into Vegas (perhaps that's a given??); it does not mention or imply that Barzini would break his deal (whatever deal that was?) with Moe.
But that doesn't mean you're incorrect. I'd just like to learn about the historical comparison that made you reach that conclusion.
