issue prepare to argue their case before a packed gallery. >> the justices' decision could change the definition of marriage in the united states. it's tuesday, march 26th. >> announcer: from abc news this is "world news now" with john muller and diana perez. tuesday, for most of us. monday for you. did you have a nice three-day weekend? >> i did. i had a good time. we had date night, which hasn't happened in a long time. >> date night for the new mom. that's always a strange thing. did you talk about the kid the whole time? >> yes. >> you're on date night but going, oh, he's so cute. >> sharing pictures with people next to us who were not interested. >> out on date night, sipping martinis talking about the kid. let's get to it. good morning. i'm john muller. the court will hear arguments. people have been lining up to witness what could become a landmark case in our country's history. >> a very big day for the issue of gay rights. we'll have more in just a moment. first, it could also be a