I think that this is a very difficult question to answer. I am not certain that there is one specific protagonist or antagonist in the drama. Part of what makes Williams' dramas so compelling is that there are no really simple answers to anything because of human consciousness being so complex and incapable of reduction to a singular element. This play is no different. Certainly, I think that an argument could be constructed that Tom is a protagonist, as we begin to understand the elements that set up the play through his narration. We also tend to understand the dynamics of the family through his perception. Yet, if we accept this, then we also have to accept the fact that Tom is not the type of protagonist that we can fully embrace or admire because of his own emotional frigidity and frail nature. While he has physically left, his emotional compass is still discombobulated. If Tom is the protagonist, then we would probably say that Laura is the antagonist. Yet, we also have to concede that our antagonist is probably more loyal from a moral standpoint because she stays while Tom leaves. The dynamic between both of them might cause this configuration to be considered in terms of protagonist and antagonist. I would also toss out there that Laura could be considered to be the protagonist. It is her life that is the center of so much discussion between brother and mother, her collection from which the play derives its title, and she represents the fundamental glue of the family. When mother and brother fight, she strives to make the peace. The play ends with her blowing out the candles of her own birthday cake, causing the audience to see her life as the center point as the lights dim. I think that Laura has a claim to being a protagonist, as well.