Your editorial “Puerto Rico’s Backlog” (Oct. 27) states that Puerto Ricans face the oligopoly power of Jones Act ships, which makes buyers of products from the mainland vulnerable to conspiracies to raise transportation prices. This issue isn’t merely hypothetical. In 2012, three Jones Act suppliers, pleaded guilty to fixing prices in their Puerto Rican trade, and six executives from two of the companies went to prison. Permanently excluding Puerto Rico from the Jones Act would be a powerful antitrust weapon.

Em. Prof. Thomas...