In the late eighties and early nineties, almost all Western European nations adopted an increasingly restrictive policy towards the growing number of asylum seekers. We develop a push-and-pull model and evaluate whether these newly created deterrence measures had a significant impact on the number of asylum applications in Switzerland. The statistical tests in the form of Box-Tiao intervention analyses shows that states are only partially able to control global migration. We particularly demonstrate that only one of the unilateral measures adopted by the Swiss government reached the main goal and led to a substantial reduction in the number of applications in 1990. Further, legal reforms did not affect the number of asylum requests of refugees fleeing from a violent conflict in the neighborhood of the host country.