According to a STORY from Catholic World News in 2004, John Kerry was excommunicated for being "personally opposed to abortion, but supports a woman's right to choose." As the story goes, a canon lawyer filed a canonical lawsuit against Kerry and received a response that because Kerry's beliefs are directly at odds with the teaching of the Catholic Church "incurs automatic excommunication."
The story goes on to quote Father Basil Cole: "If a Catholic publicly and obstinately supports the civil right to abortion, knowing that the Church teaches officially against that legislation, he or she commits that heresy envisioned by Can. 751 of the Code [of Canon Law]. Provided that the presumptions of knowledge of the law and penalty and imputability are not rebutted in the external forum, one is automatically excommunicated ...."
This being the case, Nancy isn't catholic anymore than Martin Luther was when on his deathbed.