It's always fascinating to try to decipher the ways that operatic composers use music to delineate the characters in their operas and it's certainly no less interesting to try to break the code in Vanessa. The main character is a complex person, at one point passionate or hysterical, at another haunted by memory and nostalgic for a past that will never repeat itself. Her more active, manic side is expressed in the orchestral introduction which, although dissonant, has a couple of lyrical tunes that will be used later in the opera.
After the curtain goes up Barber gives us an indication of the atmosphere in this house, where Vanessa has virtually locked herself up, where her mother the Baroness no longer speaks to her, and where the young and beautiful Erika is trapped with two older women, each of whom expresses their bitterness in different, but poisonous ways. This moment is even marked in the score, "Dark and unquiet", so that there is no question about what is being described. Musicologist John W. Freeman tells us of this moment that it sounds like "…a stalking figure, like someone pacing a room."
But Vanessa has her lyrical moments as well. In Act I, scene 2, after the ice-skating excursion with Anatol she describes to Erika the conversation she had with him and recounts, to Erika's horror, the growing love between them. In the orchestra we hear one of those long lyrical lines for which Barber is so well known. Other characters have expressive music as well. Anatol, although he's something of a manipulative cad, has some lovely music as he 'lets Erika down easily' in the second scene, telling her that he can only love her as a friend. Another interesting theme of Anatol's occurs when he warns Vanessa in Act II that "love has a bitter core". This tune recurs in the penultimate scene, after Erika's suicide attempt, when Vanessa turns to him and asks if he knows anything about it, if in some way this desperate act is related to him.
One of the most touching moments of the score is given over to Erika who, in the very first scene, looks out over the snow covered garden and sings her aria, "Must the winter come so soon?" This is one of those truly Romantic moments for which Barber is justly known. But Erika has other, shorter motives attached to her. One of them opens the second scene, after she's been seduced by Anatol and as she relates the event to her grandmother, the Baroness. This short thematic idea perfectly expresses her frustration over her erstwhile lover. The idea is developed throughout this scene and the act ends with it as she determines that she will not lay claim to him but will let Vanessa try to re-find her own long lost happiness through him.
One of the most powerful moments in the score is when Erika informs her grandmother that as a result of her rushing out of the party into the snow, she has lost the baby, Anatol's child that she was carrying. At the moment she informs the Baroness of this, the old woman rises out of her chair with a thump of her cane, turns her back on Erika and walks out of the room, to remain mute now to a second generation of women in this family, disgusted as she is by the denial of reality and the lack of courage which she finds in everyone around her. The music which accompanies this moment in the orchestra is a deformed ("aborted") version of Anatol's theme.
The music of Vanessa is certainly powerful, and expresses all of the subtle and not so subtle emotions that come to play in this sad but memorable household. Like all the truly great opera composers, Barber expresses it all perfectly through brilliant orchestration and lyrical lines for his sad, flawed characters.