It is Krogstad's blackmail that drives the play to its dramatic climax and conclusion; therefore, it is certainly an important element in the play. In considering a thesis, think of the irony in Nora's being blackmailed. What at first seems to her to be a terrible disaster turns out to be the force that finally frees her from an empty marriage and a meaningless life. Krogstad's blackmail leads directly to Nora's realizing the truth about Torvald's character. Her husband, she realizes, is a completely self-centered man who does not love her or feel any concern for her, at all. Had she not been blackmailed by Krogstad, Nora might never have discovered the truth and found a new life. Ironically, blackmail in the drama proves to be Nora's path to freedom, self-respect and personal fulfillment, a blessing in disguise.