History shows that liberal democracies are very delicate and complex political systems. Sheri Berman, a political scientist from Barnard College and author of "Democracy and Dictatorship in Europe: From the Ancient Regime to the Present Day," discusses the effort it takes to sustain the idea and practice of democracy. This is another instalment of The Democracy Agenda, a joint initiative of TVO and the Toronto Star. See omnystudio.com/listener for privacy information.