How is Blanche represented in Scene 4 of A Streetcar Named Desire?

Blanche's representation in this scene is one of the first
times that she actively begins to campaign for Stella to leave Stanley.  She is seen as
an opposing force, pulling on Stella.  In this light, Stella is poised between equally
desirable, but ultimately incompatible courses of action.  At the same time, Blanche is
shown as an individual who is placing all of her faith in Stella, and the validation
that Stella could give to Blanche.  It becomes evident that Blanche needs Stella to
leave more than anything else, as it would be more support for Blanche than anything
else.  Blanche's depiction as an opposing force in the scene is critically important in
that it starts to establish Stanley as the antagonist to Blanche.  Through Blanche's
representation in this scene, it becomes apparent that she is placing her faith in
Stella, and whether she knows it or not, is moving into an untenable
position.