But in that case, an owner of a Toyota car manufactured in Japan couldn't resell it if the GPS or audio system had components protected by copyright, said Justice Stephen Breyer. A library couldn't lend a foreign-made book, and a museum couldn't display foreign-made art, without permission of the copyright holder, he said.

Those "hypothetical" examples differ from this case, in which Kirtsaeng was importing textbooks in competition with the publisher, Olson answered.

The justices need to consider the possible effects of ruling in the favor of the textbook maker, Justice Samuel Alito countered. "We need to think about the consequences of our decision," he said.

Sections 109 and 602 of copyright law seem to conflict, said Justice Elena Kagan. "I find this language a little bit perplexing," she said. "I can kind of see it both ways."

Public Knowledge, eBay and Goodwill Industries filed briefs in support of Kirtsaeng, while the Business Software Alliance, the Software and Information Industry Association, and the Motion Picture Association of America filed briefs in support of John Wiley & Sons.