The common argument for why countries should be open to trading with each other has always been simple: free trade is good for economic growth, economic efficiency, and innovation. Businesses get access to more customers around the world, and consumers can buy a wider variety of goods and services made abroad. And for a long time, that logic was widely accepted. Countries lowered barriers to trading with each other, and global trade boomed.

Perhaps no longer. Something fundamental has changed. Policymakers are now using trade policy to pursue other goals besides just economic growth. Like national security goals, and goals related to the environment and human rights. Sometimes countries are using trade policy to fight other non-trade disputes with each other.

That is the thesis of this episode’s guest, journalist Soumaya Keynes. Soumaya has just finished a big report for The Economist magazine about this recent shift, and how it ties into the events of the past few years. The rise of populism, and the growing tensions between the US and China, and most recently the thing that’s been on a lot of people’s minds — the clogging of global supply chains.

As Soumaya explains, this new logic of trade involves complex tradeoffs for policymakers, as the non-trade goals they are now pursuing are often directly opposed to each other.