Many social movement researchers question the usefulness of political opportunity as a concept. However, others argue that it can be refined by disaggregating different opportunities for actors and outcomes to understand the underlying mechanisms that influence each. This research extends this analysis by asking "political opportunity for…

One of the defining characteristics of the late 20th and early 21st centuries is the increasing importance of international migration, an epoch Castles and Miller term the "age of migration." The precise size of the international migrant population is unknown. Much of this movement--such as unauthorized and other irregular flows--is not…