This week, as one of our LRB author specials, we talk to regular LRB contributor Jan-Werner Müller about populism, Trump and the state of democracy. Jan has long argued that populism is not just an election winning strategy, it's also a governing philosophy. We ask whether Trump's first year in office bears that out. Does he have a governing philosophy? How does it compare with other populists, from Berlusconi to Modi? And what difference does it make that he has a nuclear arsenal at his disposal? With Helen Thompson and Chris Bickerton.