Inside, captured on audiotape only, justices grilled both sides, perhaps revealing clues about how they're leaning. Listen. 

When did it become unconstitutional to exclude homosexual couples from marriage, 1791, 1868? 

When did it become unconstitutional to prohibit interracial marriages? 

Don't give me a question to my question. 

Justice Antonin Scalia showing impatience there with Ted Olson, himself a staunch conservative who is arguing for marriage rights. 

Justice Scalia later concluding that unless there's a clear answer to that question, he can't see how the court can decide the case. Obama appointee Elena Kagan on the other hand sharply questioned the attorney arguing to preserve the California same-sex marriage ban and, to his mind, preserve traditional marriage. 

It is very rare that both couples, both parties to the couple are infertile and the traditional uh, uh.

No really, because if a couple, I can just assure you, if both a woman and a man are over the age of 55, there are not a lot of children coming out of that marriage. 

Now other justices has this question whether the case even belonged before the court, fueling speculation they will be looking for a way not to make any sweeping decision. And Justice Anthony Kennedy gave voice to the danger of doing too much or too little. 

We have five years of information that, to weigh against 2,000 years of history or more. On the other hand, there is an immediate legal injury or legal, what could be a legal injury, and that's the voice of these children. There are some 40,000 children in California, according to the Red Brief, that live with same-sex parents, and they want their parents to have full recognition and full status. The voice of those children is important in this case, don't you think? 

Well, it is, to say the least, a fascinating window on history in the making, all the more when you're inside the chamber as it's happening, as senior legal analyst Jeffrey Toobin was there today, along with chief political analyst Gloria Borger. 

Jeff, in terms of other cases you have heard in the Supreme Court, how does this compare? I mean you have heard the crowd laughing. Does that happen a lot? 

Yes, there actually is often a lot of laughter. Usually, Justice Scalia tries to make a few jokes. And he made some today. Some were successful, some were not. He has a mixed batting average. But what was very unusual to me about today's argument is that usually there's a pattern. Usually you can identify what the key issues are and what the court is focusing on. What was so confusing about today is they jumped around to so many different issues and even the liberals didn't all agree on everything and the conservatives didn't all agree on everything. 

So I don't feel like I have at all much of a handle on which way this case is going, with the exception that I don't think that they are going to order 50 states to have same-sex marriage. A full complete victory for the supporters of same-sex marriage seems unlikely, but a victory in California alone does seem very possible. 

Why do you say that, Jeff? What makes you think that? 

Well, because even the liberals were concerned about going too far too fast. Justice Ginsburg raised that issue. Justice Sotomayor raised that issue of, you know, do we have to decide for all 50 states?

They seemed uncomfortable with that. And the conservatives seemed quite opposed to any sort of recognition of same-sex marriage, Scalia, Alito and even Roberts, too. 

You know, Anderson, there seemed to be a sense in the courtroom that since this issue is proceeding in the states, and public opinion is actually moving in the direction of same-sex marriage, that could work against Ted Olson in a way, because if this is proceeding in the states, then the question coming from the Supreme Court is, why do we need to do this heavy lift now?

And Justice Sotomayor seemed to be asking the question, is there any way we can make a principled decision and limit it to the state of California?