It could become illegal to resell your iPhone 4, car or family antiques.

Tucked into the U.S. Supreme Court’s busy agenda this fall is a little-known case that could upend your ability to resell everything from your grandmother’s antique furniture to your iPhone 4.

At issue in Kirtsaeng v. John Wiley & Sons is the first-sale doctrine in copyright law, which allows you to buy and then sell things like electronics, books, artwork and furniture as well as CDs and DVDs, without getting permission from the copyright holder of those products.