The purpose of this article is to respond to the question of the potential that historical institutionalism centered on actors offers for public policy analysis. It is argued that the focus centered on actors permits for a better adjustment between theoretical perspectives and observed reality in political interactions. Following this focus, the premises of institutionalism centered on actors and its model of explanation will be analyzed and the main characteristics of politics of contingents will be described in the framework of the context of globalization, the entrance of Spain into the European Union and the visible increase of the migratory flows to Spain. The potential of the focus is emphasized to explain the changes in the system of interaction of public policies of contingents and to determine the influence of the institutions and the environment on the behavior of actors.