In Romeo and Juliet, by William Shakespeare, Juliet's parents are seemingly concerned for Juliet's welfare at the start of the play. Capulet specifically tells Paris, who is vying for Juliet's hand, to wait two years to pursue her, and then, that Paris must also win Juliet's consent.
Juliet secretly marries Romeo, and then Romeo kills Tybalt. At this point, Capulet completely changes is mind (perhaps thinking Juliet grieves too much for her cousin…while she is secretly grieving more for Romeo's banishment), quickly sets a wedding date with Paris without Juliet's consent, and demands that Juliet marry Paris. Juliet demurs. Lady Capulet tells Capulet this, and he comes into the room raging. He first tells Juliet that he doesn't want to hear her polite refusals: if she doesn't agree, Capulet promises Juliet he will drag her to the church. Then he says that if she refuses, he will kick her out into the street. Lady Capulet stands up for Juliet, questioning her husband's harshness and sanity, accusing him of going too far.
Fie, fie! what, are you mad? (III.v.161)
Lady Capulet tries again.
You are too hot. (183)
The Nurse tries to defend Juliet, who is beside herself. Capulet basically tells her to shut her mouth.
And why, my Lady Wisdom? Hold your tongue,
Good Prudence. Smatter with your gossips, go! (175-176)
Capulet refuses to back down, and in an instant, Lady Capulet completely changes her tune. When Capulet leaves, Juliet's mother tells her daughter that she is finished with Juliet from here on, out.
Talk not to me, for I'll not speak a word.
Do as thou wilt, for I have done with thee. (211-212)
As quickly as Capulet can leave the room, Lady Capulet turns her back on her only child. We might assume Lady Capulet stood up to her husband in order to appear the "concerned mother," perhaps knowing as she did so that Capulet would still have his way—he is after all, the patriarch, and Lady Capulet would realistically have little (or nothing) to say in this marital arrangement. We have, however, also seen the less than gentle side of Lady Capulet. In Act One, when fighting breaks out in the streets, Capulet calls for a sword, while Lady Capulet insults him by telling him that he should be asking for a crutch. Perhaps she simply likes to defy her husband whenever possible, and does so here. Either way, we know now that she is inconstant, and will not stand behind her child.
Regardless of the reason that she decides to remove her support of Juliet, Lady Capulet contributes—in albeit a small way—to the tragedy of Romeo and her daughter, Juliet.