Also this morning, lawyers on both sides of one of the most emotional issues of american life are getting ready for battle. The supreme court has just anced it will tackle gay marriage. "Nightline"... See More
Also this morning, lawyers on both sides of one of the most emotional issues of american life are getting ready for battle. The supreme court has just anced it will tackle gay marriage. "Nightline" anchor terry moran covers the court for abc news. Terry, good morning to you. I wish you could clarify for us what's at stake here. Is it possible, I think a lot of people are wondering, that the supreme court could legalize gay marriage for the entire nation? Reporter: That's one of the choices they have. They could rewrite the law and the culture of the country, saying gay people have an equal right to get married in every state under the u.S. Constitution. That's the big kahuna for advocates of gay marriage. But they can do a lot of things short of that. One thing they could do is strike down the federal law, the defense of marriage act, which says for federal purposes, tax benefits, access to people in hospitals, marriage is only between a man and a woman. They could just strike down that one and leave the rest up to the states. There's a whole range they could do. Are the justices in any way influenced by the changing public opinion on this issue? We've seen a dramatic shift in favor of gay marriage. Reporter: That's the most interesting question in this case, dan. Ten years ago, the supreme court would have decided this one way, probably unanimously or close to that. Ten years from now, it will go the other direction. We're right at the hinge of history on this issue. Does the supreme court crystallize what seems to be this emerging consensus, as you point out? Or as conservatives should do, yelling stop. The court has this really interesting moment in which to decide one of the most controversial issues we are discussing today. At the hinge of history. A lovely phrase. Terry moran, anchor of "nightline," who anchored "nightline" last night, up early with us. We appreciate it. Thank you, dan.
This transcript has been automatically generated and may not be 100% accurate.