Zoellick has written extensively on foreign policy and international economics. He is a proponent of free trade. In a September 2017 article, he urged Congress to assert its constitutional powers over trade before Trump's policies "unravel vital ties across the Asia-Pacific region, hurt an ally facing a security crisis, destroy a North American partnership ... and subvert confidence in the U.S. around the world." He contributes opinion pieces to the Financial Times, Washington Post and the Wall Street Journal. Zoellick is the author of America in the World.