Shortly after noon on January 20, America’s newly installed president issued a declaration of war against global free trade. “We must protect our borders from the ravages of other countries making our products, stealing our companies, and destroying our jobs. Protection will lead to great prosperity and strength,” Donald Trump said in his inaugural address. “We will follow two simple rules: Buy American and hire American.”

One of the big questions surrounding the Trump presidency is just how aggressively he’ll advance protectionism. The new Republican president, who has changed his party affiliation five times as an adult, is famous for his bluster and shifting political views. But his mercantilist position that international trade is a zero-sum game is perhaps the most consistent political belief he’s ever held. Back in the 1980s he warned that Japan was ripping us off. Now China and Mexico are the two biggest threats. “I’d love to have a trade war with China,” Trump said in a 2010 interview on Fox Business. “If we did no business with China, frankly, we’ll save a lot of money.”