Native Sons

By including Max's very long presentation of his case, Richard Wright is leaving very little to be guessed by the reader. By reading this, the reader pretty much knows exactly what Richard Wright is trying to say by telling Bigger's story because he essentially spells it out.
In the end, though, it did not matter how great of a speech it was that Max made because Bigger still got charged, but this likely would have been true regardless of what Max had said given Bigger's situation. I think that Max knows this, and that is why he says the things he says. Max is just trying to tell the truth, to bring the issues at least into public eye, while also trying as hard as he possibly can to save Bigger's life.
Part of the reason that Bigger's life is not saved is that Max's speech makes the trial not just about Bigger. Max makes the trial about everyone. Every black citizen, and every white citizen. He argues that Bigger's crime is much more than just his crime, that it is instead society's crime. And this means that everyone is to blame. If Bigger were not to be given the death sentence, that would have been seen as an acknowledgement of the jurors that something in the society is wrong which would mean that they were wrong, which is something no one wants to admit to. Max brings to light the deeply flawed society that they all live in, but because the flaws do not necessarily affect them, they feel no need to change them.
Buckley's speech, which is not nearly as eloquent or thought-provoking as Max's is the one that "wins" because Buckley tells everyone exactly what they want to hear. This case was not about what was right or wrong, it was about what the white people wanted, and so that is what prospered, as it did all throughout Native Son and throughout history.