Justin Webb looks back at the five big US foreign policy shifts from the Monroe Doctrine to Donald Trump. Over five episodes he and his guests look at how America’s approach to the world has constantly changed over time. This may help answer a really big question - how radical is the way Donald Trump deals with the world? Is he really an outlier in US history? Or do his actions reflect the changing patterns of American power?

In this episode Justin discusses the Reagan Doctrine with Kathleen Burk, Emeritus Professor in Modern and Contemporary History at University College London and Professor Sir Lawrence Freedman, Emeritus Professor of War Studies at King's College London.

Presenter: Justin Webb Producers: Caroline Bayley and Kirsteen Knight Researcher: Helena Warwick-Cross Editor: Jon Bithrey Sound engineer: Tom Brignell

Credit: Reagan’s State of the Union Address courtesy of the Ronald Reagan Presidential Library