In The Merchant of Venice, Portia plays a crucial role in the development of the plot. She represents everything that Shylock, the other main character, does not and is the epitome of all that is good and fair. She feels cornered by her deceased father's limits on her marriage choices but, despite being "curbed by the will of a dead father" (I.ii.25) she ensures that the outcome of choosing a suitor, over which she has no apparent say, works in her favor.
Portia's behavior in the face of her late father's actions prove that she is a strong character, intelligent and resourceful, making the best of any situation. Portia has a strong sense of duty - as she adheres to her father's wishes but her ingenuity ensures that the suitor whom she desires - Bassanio - chooses the correct casket and wins the right to marry her. She does betray a degree of petulance as the Prince of Morocco arrives to make his choice and the audience is aware that she does NOT approve.
Her behavior allows the women of her time to relate to her and wish to perhaps emulate her, desperately wishing they could be more like her. While she is dutiful, she is also a convincing and even compelling character. This continues when she intervenes in the dispute over the "pound of flesh."
Dressed as a man, Portia is able to show her versatility and absolute measure of fairness. "Mercy....is an attribute of God himself" (IV.i.195)It is this very characteristic that allows her to standf up in court in a completely unfamiliar position, a position that places an enormous amount of responsibility on her and still maintain her composure. She is not afraid to stand her ground and even enjoys the role-playing and the feeling of power it gives her.
She has been able to fulfill her father's wishes without being weak-willed or subservient , as many of the women in her day would have been and at the same time get her own way; furthermore, she can manipulate situations, even having a little playful banter with Bassanio over his wedding ring. Women of her day would have loved to be in such a position where they could interact with their husbands in this way.
Modern women can also relate to Portia due to her capacity to adapt to change. She is multi-faceted - definitely a requirement in the modern-day when women need to be homemakers, career women, loving wives and mothers, and so on.