Stockard Channing = C+
I really don't understand why Channing got an Oscar nomination for this, to tell you the truth. Not that I don't like Channing; she's a fantastically gifted actress who worked wonders in The Business of Strangers, The West Wing and even Grease. But I don't understand the love or at least acclaim that this performance has received. Perhaps I don't get the movie, perhaps I don't get the performance; but I found Channing to be quite simply stagey and overly shrill. The only feeble defence I can put up for her is that the film is stagey and far too pretentious, or at least trying to hard to parody pretentious that it still ends up being the thing it tries to parody. Channing isn't asked to perform a character as much as she is a symbol of upper class phoniness.
Donald Sutherland = C
Sutherland fairs only slightly worse than Channing in his role; which is a little bit more well defined than Channing's is, but it's a very stuffy character without any depth or detail to it. However, Sutherland aims for a more restrained performance than Channing does, but for whatever reason, he fails to achieve any nuance with that restraint. It's not to say that I don't love Sutherland, he's a supremely underrated actor who has been so since the 1970s. However, this performance should be one of his forgotten ones; it's not bad or anything. It's just not good.
Will Smith = B
Smith gives the best performance in the film, which should more accurately be defined as the least dull in the film. Much like Jennifer Garner in Juno, this is because he's given the least hackneyed dialogue in the film. With the exception of his scenes with the above two actors and their characters, he's gifted with rather natural dialogue that he sells quite easily. His character is a little bit of a cipher, he's very hard to define and even by the end of the film we don't really know him, which isn't so much as a knock on Smith as it is, once more, on the script. However, Smith has brief moments where he lets his indelible charisma shine through, and this performance foreshadows his better work in the likes of Ali and The Pursuit of Happyness.
Overall Film Grade: C-