The Old South and the New South: Stella and Blanche come from a world that is rapidly dying. Belle Reve, their family's ancestral plantation, has been lost. The two sisters, symbolically, are the last living members of their family. Stella will mingle her blood with a man of blue-collar stock, and Blanche will enter the world of madness. Stanley represents the new order of the South: chivalry is dead, replaced by a "rat race," to which Stanley makes several proud illusions.
Cruelty: The only unforgivable crime, according to Blanche, is deliberate cruelty. This sin is Stanley's specialty. His final assault against Blanche is a merciless attack against an already-beaten foe. On the other hand, though Blanche is dishonest, she never lies out of malice. Her cruelty is unintentional; often, she lies in a vain effort to plays. Throughout Streetcar, we see the full range of cruelty, from Blanche's well-intentioned deceits to Stella self-deceiving treachery to Stanley's deliberate and unchecked malice. In Williams' plays, there are many ways to hurt someone. And some are worse than others.
The Primitive and the Primal: Blanche often speaks of Stanley as ape-like and primitive. Stanley represents a very unrefined manhood, a romantic idea of man untouched by civilization and its effeminizing influences. His appeal is clear: Stella cannot resist him, and even Blanche, though repulsed, is on some level drawn to him. Stanley's unrefined nature also includes a terrifying amorality. The service of his desire is central to who he is; he has no qualms about driving his sister-in-law to madness, or raping her.
Desire: Closely related to the theme above, desire is the central theme of the play. Blanche seeks to deny it, although we learn later in the play that desire is one of her driving motivations; her desires have caused her to be driven out of town. Desire, and not intellectual or spiritual intimacy, is the heart of Stella's and Stanley's relationship. Desire is Blanche's undoing, because she cannot find a healthy way of dealing with it: she is always either trying to suppress it or pursuing it with abandon.
Loneliness: The companion theme to desire; between these two extremes, Blanche is lost. She desperately seeks companionship and protection in the arms of strangers. And she has never recovered from her tragic and consuming love for her first husband. Blanche is in need of a defender. But in New Orleans, she will find instead the predatory and merciless Stanley.
