Read More: Q&A: Justice Breyer’s Full Interview With The NLJ

A decade ago, conservative members of Congress railed against the Supreme Court for citing foreign court rulings or norms in deciding U.S. cases. Breyer’s new book calls those attacks “beside the point,” because it is no longer possible to ignore what other courts around the world are saying.

“What I want to do in the book,” Breyer said in the NLJ interview, “is not just to refute somebody but to acquaint you and others—not just lawyers and judges but generally—with the nature of the actual problems that now take up maybe 15 or 20 percent of our docket, because they’ll show you how the world has changed.”

The book examines the range of cases in which the high court has looked beyond U.S. borders for insight on matters that include copyrights, antitrust, securities law and Guantánamo Bay.

Most of the cases brought by Guantánamo detainees were a defeat for executive power. Breyer highlights the admonition, in one of the cases, from his close friend retired Justice Sandra Day O’Connor, who said a state of war does not write “a blank check for the president.”

Breyer asked, rhetorically, “If it doesn’t, what kind of check does it write? If you write a blank check, you end up with Korematsu. On the other hand, if you say nothing special is going on, how is the court, or the president, or the Congress supposed to deal with real security problems?” Breyer was referring to the 1944 case, Korematsu v. United States, that upheld the internment of Japanese-Americans during World War II.

Cases that test the balance between civil liberties and national security “will not go away,” Breyer told the NLJ, one of several media outlets that spoke with the justice in advance of the publication of his book. “There are issues of privacy floating around. There are issues of all kinds of things, and the courts are sort of struggling with it.” By laying out the issues in language that nonlawyers can grasp, Breyer said, “This book in a sense is a kind of report from the front.”

Dramatic dissent

In the interview Breyer also responded to questions about the last term of the Supreme Court and his dramatic dissent in the death penalty case Glossip v. Gross. Breyer said the time has come again for the court to decide whether capital punishment has become so flawed and arbitrary that it should be found unconstitutional under the Eighth Amendment.

Breyer confirmed that he had written the dissent before the Glossip case arose. “I have been working on it for a while,” he said. “This case was there, and it seemed an appropriate place to say what I thought on the issue.”

Related: Challenge to Lethal-Injection Procedure Fails in Supreme Court