Episodes each Wednesday through labor day. Find all the episodes from this season here. And past seasons here. And follow along on TikTok here for video Summer School. Trade has come up in all of the episodes of Summer School so far. An early use of money was to make trade easier. Trade was responsible for the birth of companies and the stock market. And trade was the lifeblood of the early United States.Today's episode covers 250 years of trade history in three chapters. We start with one of the founding texts of economics, Wealth of Nations, in which Adam Smith argues a country's true value is not measured in gold and silver, but by its people's ability to buy things that enhance their standard of living. Then we'll watch American politicians completely ignore that argument in favor of protecting domestic industries - until one congressman makes a passionate case for free trade as the means to world peace. And finally we'll follow the trade debate up to the modern day, where the tides of American politics have turned toward regulation.This series is hosted by Robert Smith and produced by Audrey Dilling. Our project manager is Devin Mellor. This episode was edited by Planet Money Executive Producer Alex Goldmark and fact-checked by Sofia Shchukina. Subscribe to Planet Money+ for sponsor-free episode listening in Apple Podcasts or at plus.npr.org/planetmoney.