Alliance Treaty Obligations and Provisions, 1815-1944

This article introduces the Alliance Treaty Obligations and Provisions (ATOP) dataset. We begin by describing the rationale for collecting the ATOP data, its scope, and some general coding rules for the project. Then we offer some descriptive statistics for phase one of the dataset, which covers the years 1815-1944, and reveal some interesting trends in alliance politics. Finally, we replicate a study of alliance formation originally conducted by Lai and Reiter (2000) to demonstrate the effect the use of ATOP data may have on past inferences about alliance politics.