Drug traffickers sometimes share profits peacefully. Other times they fight. We propose a model to investigate this variation, focusing on the role of the state. Seizing illegal goods can paradoxically increase traffickers' profits, and higher profits fuel violence. Killing kingpins makes crime...

Vaccinating the world's population quickly in a pandemic has enormous health and economic benefits. We analyze the problem faced by governments in determining the scale and structure of procurement for vaccines. We analyze alternative approaches to procurement. We find that if the goal is to...