This article discusses the content and causes of emergency powers in democratic states. It makes two main contributions. First, it introduces the Democratic Emergency Powers dataset, which codifies formal rules of institutional change during periods of emergency for all democracies from 1800 to 2012. These data are important because often state institutions in times of emergency differ dramatically from those in times of relative peace, and this influences government decision-making during times of crisis. I discuss the collection process and develop a measure of the latent strength in each of these emergency provisions. Second, this article examines the determinants of emergency power strength in democratic nations cross nationally. I find that previous and current conflict experience influence emergency power provision and strength, but also that domestic determinants have an impact on the types of instruments states institutionalize for times of emergency.