"Justice Stevens who was dissenting, said you may not by this kind of secret transfer of an American citizen defeat an American citizen's access to the civil courts to try the legality of his detention," Souter said.
Asked how important that was, Souter told Pelley, "It's as fundamental as any decision that's been made that I can think of on a citizen's liberty in my lifetime."
"And it was Justice Stevens who stood up and said, 'Wait a minute. This has gone too far,'" Pelley remarked.
"That's what you got courts for. He was earning his salary," Souter replied.
"He rendered a service to the country in those opinions?" Pelley asked.
"Yeah. That made him one of the great judges," Souter said.
"I would imagine that the majority of the American people would probably disagree with you on these opinions," Pelley told Stevens.
"That may very well be true," he replied. "You know it's a part of our job to write opinions from time to time that are not popular and you know at the time they're not going to be popular."
Stevens took us on a tour of the hidden Supreme Court. There is a library that's usually open only to lawyers; it's not used much now that there's Internet. And he gave us rare access to the justices' "robing" room.
"It looks like a locker room," Pelley remarked.
It's in the robing room that all nine justices slip into their gear and, by tradition, shake hands at the start of the new term. We were with Stevens in June as he was preparing to hang up his robe for the last time and it was then that he told us he was worried about the direction of the court.
The Supreme Court is supposed to uphold the Constitution, but throughout its history there has always been tension when justices appear to rewrite laws that Congress was elected to write.
It is called "legislating from the bench." Stevens says one of the worst examples came this year in a case called "Citizens United." The court majority overturned 100 years of law that limited corporate money in politics.
Stevens told Pelley he thought the court had legislated from the bench.