Colin Vanderburg: Let’s start with some definitions. Who belonged to these two broad political-economic camps—protectionism or economic nationalism on one side, and free trade on the other? How were these terms understood in the 19th-century and early 20th-century contexts that are the focus of the book? Marc-William Palen: First, there were material interests at work: those who tended toward free trade were more export-oriented or consumer-oriented, focused on lowering costs for consumers, or on allowing for increased exports to new markets, freeing up domestic markets as well. By contrast, economic nationalist and protectionists tended to prefer high tariffs to protect domestic industries from the full force of global competition. I try to show that there were also geopolitical aspects to both these positions that don’t get as much attention as their material aspects.…