When U.S. President Donald Trump announced the imposition of his “Liberation Day” tariffs against most of America’s global trading partners in April 2025, he seemed to harken back to a centuries-old form of economic nationalism known as mercantilism, which sought prosperity through restrictive trade practices. Opponents of mercantilism from the eighteenth century onward, such as Adam Smith and John-Baptiste Say, became known as classical liberals. In the fullness of time, classical liberalism gave rise to the political philosophy we now know as libertarianism.

When most people think of libertarianism, they typically have in mind a small number of figures — including Milton Friedman, Friedrich Hayek, Ayn Rand, Murray Rothbard, and Ludwig von Mises — who were generally associated with the American political right in the mid-twentieth century. But in fact libertarianism was born in the nineteenth century (not the twentieth), and was first developed in Britain and France (not the United States). And as Matt Zwolinski emphasizes in his monumental intellectual history of libertarianism, The Individualists (co-authored with John Tomasi), libertarianism is better thought of as a cluster of related concepts than a unitary doctrine. 

It’s true that most libertarians historically have been concerned with the defense of individual autonomy, property rights, free markets, and personal liberty against state coercion. But the first individual to self-identify as a “libertarian” was the nineteenth-century French anarcho-communist Joseph Déjacque, and libertarianism as it developed often took radical and left-leaning forms, particularly through its association with the abolitionist movement in America in the years before the Civil War. 

In this podcast conversation, Matt Zwolinski (a philosophy professor at the University of San Diego) discusses his investigations into the intellectual history of libertarianism as well as his analysis of the longstanding tensions between radical and reactionary elements within the philosophy. He describes post-Cold War “third wave libertarianism” taking both right-wing expression (in the form of paleolibertarianism) as well as more radical forms (including left-libertarianism and “bleeding-heart libertarianism.”) And he suggests reasons why many libertarians see more potential in combating poverty through Universal Basic Income grants rather than through more traditional government-administered antipoverty programs.