Supreme Court Justice Stephen Breyer discusses his recent book "Active Liberty: Interpreting Our Democratic Constitution," his judicial philosophy and changes in the court since Chief Justice John Roberts' arrival.

JAN CRAWFORD GREENBURG: Thank you for joining us today, Justice Breyer. Tell us why you decided to write this book.

JUSTICE STEPHEN BREYER: I wanted to write it because I've learned from really Chief Justice Rehnquist, Justice O'Connor, my predecessor Harry Blackmun that there's a tremendous desire for knowledge about the court and how do we actually decide cases? People want to know. It's not the CIA; there's not really a secret. And I wanted to try to help people understand that.

And also, I think there's a misconception. I think that many people believe that we're deciding what's good or bad for Americans. That's not the job of the court in constitutional cases. The job is really to look at the Constitution which sets boundaries, vast space in between those constitutional boundaries. That space is for people to decide for themselves what they want. And we're just policing the far boundaries of that space.

JAN CRAWFORD GREENBURG: Well, now, the way you describe your approach to looking at cases and deciding cases is active liberty, to get more people involved in democracy and in the process. Can you elaborate on that a little bit.

JUSTICE STEPHEN BREYER: I think after eleven years on the court, a judge on our court begins to through a steady diet of constitutional cases see the document as a whole. I think most of us when we look at it, if asked what kind of document is it, would say it is a document that creates democratic political institutions. It's a certain kind of democracy. It's a democracy that protects basic human rights. It assures a degree of equality. It divides power so that no group becomes too powerful: states, federal government, three branches of government. And it insists on a rule of law.

Now I want to show that that isn't just the subject of a 4th of July speech but that those general purposes help us directly decide difficult cases and in particular the democratic part which is at the heart of the institution.

JAN CRAWFORD GREENBURG: Let's apply it. The First Amendment says that Congress shall make no law respecting the establishment of a religion. And you have at times parted ways with some of your more liberal colleagues to allow for more religion in public life we saw in the Ten Commandments. How does active liberty come into play and allow you to reach those results?

JUSTICE STEPHEN BREYER: Well, I wanted to use that in the book really to illustrate the importance of looking back to the basic purpose of the underlying provision. In the case you mentioned the establishment clause of the First Amendment. The religion clauses were designed in significant part to try to temper religious disputes: The social dissension that grows out of the fact that people have different religions.

And it's easy to get a lot of social dispute, tension, dissension, et cetera. But remembering that as a basic purpose, then I would look at the consequences in the particular Ten Commandments case -- that's what I wrote about. That's what I did.

In one of the cases, the Ten Commandments monument was being given to a courthouse, put in the courthouse by people who had primarily religious motives. It was tension building. It led to dispute about religion -- religious-related dispute. And I thought given the purposes, that falls on the forbidden side.

The other had been a monument on the Texas state capital for about 40 years with about sixteen, seventeen other monuments that had nothing to do with religion. It was labeled the ideals of Texans. It never disturbed anybody. And I thought, well, if that's forbidden is what I wrote, if that's forbidden, people might go around and try to chip Ten Commandments off of public buildings all over the United States. And that, too, would cause a lot of religious dispute.

So, I thought, well, the one falls on the permitted side, the second. And the first falls on the forbidden side because I refer back looking at the consequences in terms of the basic purpose of the religion clauses.

JAN CRAWFORD GREENBURG: A criticism of this court though has been that it reaches out and takes disputes away from the people and out of the political process, that unelected judges are making those decisions on consequences that perhaps should be left to the people. What's your response to that? I mean, are you skeptical of the political process's ability to handle those kinds of controversial cases?

JUSTICE STEPHEN BREYER: I think that's a good criticism, not a bad criticism even if I disagree with it in particular cases. And the reason is, it suggests what I think is absolutely true: That the reason that the court is there is to police the outer boundaries. The Constitution creates a democratic space where people are supposed to make decisions for themselves. That's the point. It foresees that they will participate in government making their own decisions.

Now what the court does, as I said, is police the outer boundaries. And when you get to the outer boundaries and you have a case that arguably is outside the boundary, some people might think, you shouldn't have said it was outside the boundary. And other people will think, you should have said it was outside the boundary. That's the nature of disputes about the court.

I can't say we always make the right decision. I can say the best we can do is try. And the kind of dispute, I repeat, is: Was this outside the boundary or wasn't it? And, of course, it's not surprising that people disagree when you're right in that borderline area.

JAN CRAWFORD GREENBURG: When you came on to the court, you had been on the federal appeals court for 14 years, professor at Harvard Law School. What was the most surprising thing or what was different than you had expected?

JUSTICE STEPHEN BREYER: Well, if I admit it, you know, on an appeals court, a judge writes about 50 opinions a year. And there are maybe 300 cases on the docket. You may participate in 150 cases, more than that. So I thought I knew that the Supreme Court justice typically wrote about 20 or so. And there were only about 80 cases to decide. I thought, well, this is going to be quite easy really. Ha, ha, ha.

It's not easy one little bit. Every one of those cases is as difficult as any case I had on the appeals court which is not surprising because we select the docket in order to have those cases where the country, in our view, needs a uniform rule of federal law.

And it's most likely to need a uniform rule of federal law if the lower courts have come to different conclusions on the same issue of federal law. So they're the hardest cases. A member of the court has to be really up on every one of those cases. That means for every one of those cases I have to have read quite a large number of briefs, talked it over. I usually talk it over with my law clerks. Then we have oral argument. I go back to the briefs.

We talk it over at conference. We write opinions. And then we read each other's drafts pretty carefully, make suggestions. I'm always amenable to suggestions when I'm writing particularly before I have five members on my opinion.

And in other words, it's supposed to be, it is what it's supposed to be. It's very, very serious work. It's difficult and it calls for me and the others to give to that job what we have that is best within us -- our best ability. And it doesn't let up.

And that is a privilege, a real privilege to have a job like that as you grow older. It is a privilege to have a job that requires you to do your best, to try to do your best every minute.

JAN CRAWFORD GREENBURG: Now, this court has been together, this most recent court 11 years the longer of any court of nine justices in history. Some people say it's liberal; some people say it's conservative. How do you characterize the court?

JUSTICE STEPHEN BREYER: I suspect that you like to characterize it in terms of - you're in journalism -- of what newspapers call liberal or conservative. But that isn't basically what moves us. We do respond to the particular cases.

JAN CRAWFORD GREENBURG: You know, Justice White used to say that a new member meant a new court. And obviously we have a new chief justice now and a new member soon will be joining. Why is that? Why isn't it just a new member is a new vote? Tell us about that.

JUSTICE STEPHEN BREYER: The dynamics. It's fine to change. I mean the change is fine. No one, as you get older, things change. And we're nine people. And we in the conference room listen to each other. We're not always persuaded by each other but each of us is sitting there taking notes on what every other member of the court says.

And the key I think to that conference is that people are giving their real reason. They're not sitting there saying, ha, ha, I have a better argument than you have or vice versa.

The point is to say what you really think, what are the real reasons that lead you to decide the case this way. And as long as the discussion proceeds at that level, it's productive. And of course there is a dynamic with nine people. I suppose that's what Justice White was referring to. I've only seen the one court except for the last month or so. So I can't really tell you.

JAN CRAWFORD GREENBURG: And how has the last month been with your new leader?

JUSTICE STEPHEN BREYER: Fine, fine, very nice.

JAN CRAWFORD GREENBURG: But obviously even the arguments seem to have somewhat of a different feel.

JUSTICE STEPHEN BREYER: That, you'll have to judge.

JAN CRAWFORD GREENBURG: But have you noticed any changes or have there been any differences in the conference?

JUSTICE STEPHEN BREYER: Well, my prediction is we have gotten on well for 11 years and we'll continue to get on well.

JAN CRAWFORD GREENBURG: Well, it's certainly been a privilege having you here with us, Justice Breyer. Thank you very much.

JUSTICE STEPHEN BREYER: Thank you.