Now to the supreme court and those emotional arguments over gay marriage. At issue yesterday, the federal law defines marriage as a union between a man and woman. At the heart of the case an... See More
Now to the supreme court and those emotional arguments over gay marriage. At issue yesterday, the federal law defines marriage as a union between a man and woman. At the heart of the case an 83-year-old pioneer. Our supreme court expert "nightline's" terry moran is here with her story and what to expect from the court. Good morning, terry. Reporter: Good morning, george. All quiet. No protesters, no arguments but the justices are at work getting ready for their weekly conference, one of the most secret meetings in washington, only nine of them, that will be tomorrow morning. They'll take their first votes on the issue of same-sex marriage and the constitution and an issue which comes to them in part out of the life and love of one remarkable american woman. All: Edie, edie. Reporter: This morning edie windsor is celebrating after having her day in court and what a day it was. This 83-year-old woman has become a kind of folk hero to countless young americans. I'm talking to you freely. I'd have been hiding in the closet ten years ago. Reporter: Her case arises from the love of her life, thea spire, they spent 44 years ago finally marrying in 2007. But af thea died in 2009, edie was suddenly hit with $363,000 in estate taxes, taxes no straight widow would have to pay because the federal government refused to recognize their marriage under the defense of marriage act. In court, justice ruth ginsburg said it seemed like a second class system for gay couples. Two kinds of marriages, the full marriage and then this sort of skim milk marriage. Reporter: That comment struck a cord on social media becoming a popular twitter hashtag but for millions of americans it's no laughing matter. Same-sex marriage is about bedrom beliefs. We're not motivated by bigotry. We just believe that when the god of the bible created the institution, he defined it, and I really believe that he got it right. Reporter: Edie windsor and thea spire were engaged way back in 1967. But told thea she wouldn't be able to wear a ring because all of her colleagues at ibm would say who's the guy. So she got a diamond broach which she was wearing in that court yesterday. What a story. What a story. All right, terry, thanks so much.
This transcript has been automatically generated and may not be 100% accurate.