The study was inspired by the puzzling three-fold evolution of labor migration policies over the last sixty years: Why in the post-Cold War period did Germany espouse temporary, rotation-oriented migration policies (TFWPs); the United States permanent, settlement-oriented migration policies (PFWPs); and France as well as Spain a hybrid of both?

The study argues that scholars and policymakers alike have paid insufficient attention to the gradually unfolding causes and effects of critical junctures in the history of international labor migration. Having sought to explain continuity and change in international labor migration through the prism of immediate causes and effects of what they considered historical turning points, scholars and policymakers have been unable to explain why e.g. Switzerland began to cap TFWPs years before the putative break point constituted by the 1973/74 oil shocks and why Germany revived the TFWPs nearly twenty years thereafter.

Not only have scholars and policymakers applied too narrow analytical frames to the period during which change occurred, but also to the actors who drove it. The study argues that at certain junctures policymakers become uncertain about what migration policy objectives should be, and thus become more open to the ideas provided by TFWP advocates on the one hand and by PFWP advocates on the other hand. In order to understand whose ideas are likely to influence policy at which junctures, the study adopts a historical institutionalist approach and develops a model of labor migration policy ebbs and flows. The three main building blocks of this model are: antecedent conditions, critical junctures, and legacy.

During the antecedent conditions, the advocates of an eclipsed policy expand coalitions in order to socialize policymakers to the idea that their migration policy is more adequate than the incumbent. There are at least three ways in which the advocates of change can gradually socialize policymakers to their interpretation of what migration policy should be: layering, conversion or drift. During a critical juncture, policymakers may yield to the ideas of new policy advocates and displace the old policy and its advocates to the fringe of the policymaking sphere. Nonetheless, during the early phases of a legacy period, the advocates of the old policy contest the newcomer. Whether a new policy will persist in the context of contestation by aggrieved defenders of an eroding old paradigm depends on its ability to self-reproduce in the absence of the original cause. In this respect, while based on path-dependence, the proposed model assumes an open-ended form of it, because social phenomena, such as migration, lend themselves much more to contestation than technology.

Having applied empirical evidence from the evolution of Spanish, French, and to lesser extent U.S. and German labor migration policies since 1945 to the theoretical model developed in the first chapter, the study has found that international labor migration in all of the countries has evolved through a constant battle of policy paradigms. In certain junctures, policymakers favored the arguments of TFWP advocates, in other junctures, those of PFWP advocates. But they have never been able to move beyond the politics of labor migration. In this respect, the most important path not-taken has not been that of TFWP or PFWP, but that of a historically and geographically coherent migration policy in the form of a labor migration regime.