Jack N. Rakove, Pulitzer Prize Winner; Stanford University, U.S., discusses "Trumping the American Constitution: A Genuine Crisis?" as part of the American Foreign Policy Series.

Luuk van Middelaar, Leiden University, The Netherlands, discusses "Improvisations — The New Politics of Europe" as part of the Contemporary History and Institutions of the Mediterranean Series.

Christoph Engel, Max Planck Institute for Research on Collective Goods, Germany, discusses "Helping When Need Cannot Be Proven" as part of the International Development Economics Series.

Richard Rogers, University of Amsterdam; Digital Methods Initiative; Netherlands Research School for Media Studies, The Netherlands, discussed "Otherwise Engaged: Social Media from Vanity Metrics to Critical Analytics" as part of the Politics Beyond the State: Politics in the Internet Era Series.

Guido Tabellini, Bocconi University, Italy, discusses "Is Europe an Optimal Political Area?" as part of the International Economics Series.

Robert Elgie, Dublin City University, Ireland, discusses "Is Presidentialism Perilous? The Results of a Laboratory Experiment" as part of the Understanding the New Europe Series.

Soli Ozel, Kadir Has University, Turkey, discusses "The Grand Delusion: The Rise and Fall of Turkey's Regional Ambitions" as part of The Middle East: Understanding the Role of Regional and External Powers Series.

Frederic Bozo, Sorbonne Nouvelle (University of Paris III), France, discusses "France, Europe and Transatlantic Relations" as part of the American Foreign Policy Series.

Sanam Vakil, Johns Hopkins University SAIS Europe, Italy; Chatham House, U.K., discusses "Iranian Domestic and Regional Politics in the Age of Trump" as part of The Middle East: Understanding the Role of Regional and External Powers Series.

Aline Sierp, Maastricht University, The Netherlands, discussed "The Unbearable Lightness of Dates. Remembering the End of the Cold War in the EU" as part of the Understanding the New Europe Series.